### Godot version

4.0 RC1

### System information

Linux Mint 20.3 Cinnamon

### Issue description

Tried converting a 3.5 game to 4.0 RC1. The conversion popup menu closed after a few seconds, and trying to edit the game crashes the entire engine with the following errors, which seem to be related to one music file not loading:
![errors](https://user-images.githubusercontent.com/125468288/219127087-f5a78035-4e4a-4625-aadb-e0cde6d5ac3d.png)

Not sure what's causing the issue, because when I created a new project with only that file and converted it I didn't get these errors, but consistently get them when trying to convert that game.

### Steps to reproduce

- Download the reproduction project below
- Import in Godot 4.0, and click "convert full project"
- If the bug happens, the engine will crash whenever trying to edit or run the converted project

### Minimal reproduction project

[Music Convertor Crash Demo.zip](https://github.com/godotengine/godot/files/10746591/Music.Convertor.Crash.Demo.zip)

bool valid = true;
	valid = valid && test_conversion_with_regex("tool", "@tool", &ProjectConverter3To4::fix_tool_declaration, "gdscript keyword", reg_container);
	valid = valid && test_conversion_with_regex("\n    tool", "\n    tool", &ProjectConverter3To4::fix_tool_declaration, "gdscript keyword", reg_container);
	valid = valid && test_conversion_with_regex("\n\ntool", "@tool\n\n", &ProjectConverter3To4::fix_tool_declaration, "gdscript keyword", reg_container);
	valid = valid && test_conversion_basic("TYPE_REAL", "TYPE_FLOAT", RenamesMap3To4::enum_renames, reg_container.enum_regexes, "enum");
	valid = valid && test_conversion_basic("can_instance", "can_instantiate", RenamesMap3To4::gdscript_function_renames, reg_container.gdscript_function_regexes, "gdscript function");
	valid = valid && test_conversion_basic("CanInstance", "Can", RenamesMap3To4::csharp_function_renames, reg_container.csharp_function_regexes, "csharp function");
	valid = valid && test_conversion_basic("translation", "position", RenamesMap3To4::gdscript_properties_renames, reg_container.gdscript_properties_regexes, "gdscript property");
	valid = valid && test_conversion_basic("Translation", "Position", RenamesMap3To4::csharp_properties_renames, reg_container.csharp_properties_regexes, "csharp property");
	valid = valid && test_conversion_basic("NORMALMAP", "NORMAL_MAP", RenamesMap3To4::shaders_renames, reg_container.shaders_regexes, "shader");
	valid = valid && test_conversion_basic("text_entered", "text_submitted", RenamesMap3To4::gdscript_signals_renames, reg_container.gdscript_signals_regexes, "gdscript signal");
	valid = valid && test_conversion_basic("TextEntered", "TextSubmitted", RenamesMap3To4::csharp_signals_renames, reg_container.csharp_signal_regexes, "csharp signal");
	valid = valid && test_conversion_basic("audio/channel_disable_threshold_db", "audio/buses/channel_disable_threshold_db", RenamesMap3To4::project_settings_renames, reg_container.project_settings_regexes, "project setting");
	valid = valid && test_conversion_basic("\"device\":-1,\"alt\":false,\"shift\":false,\"control\":false,\"meta\":false,\"doubleclick\":false,\"scancode\":0,\"physical_scancode\":16777254,\"script\":null", "\"device\":-1,\"alt_pressed\":false,\"shift_pressed\":false,\"ctrl_pressed\":false,\"meta_pressed\":false,\"double_click\":false,\"keycode\":0,\"physical_keycode\":16777254,\"script\":null", RenamesMap3To4::input_map_renames, reg_container.input_map_regexes, "input map");
	valid = valid && test_conversion_basic("Transform", "Transform3D", RenamesMap3To4::builtin_types_renames, reg_container.builtin_types_regexes, "builtin type");
	valid = valid && test_conversion_basic("custom_constants/margin_right", "theme_override_constants/margin_right", RenamesMap3To4::theme_override_renames, reg_container.theme_override_regexes, "theme overrides");
	
	valid = valid && test_conversion_with_regex("(Connect(A,B,C,D,E,F,G) != OK):", "(Connect(A, new Callable(B, C), D, E, F, G) != OK):", &ProjectConverter3To4::rename_csharp_functions, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("(Disconnect(A,B,C) != OK):", "(Disconnect(A, new Callable(B, C)) != OK):", &ProjectConverter3To4::rename_csharp_functions, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("(IsConnected(A,B,C) != OK):", "(IsConnected(A, new Callable(B, C)) != OK):", &ProjectConverter3To4::rename_csharp_functions, "custom rename", reg_container);
	valid = valid && test_conversion_with_regex("[Remote]", "[RPC(MultiplayerAPI.RPCMode.AnyPeer)]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[RemoteSync]", "[RPC(MultiplayerAPI.RPCMode.AnyPeer, CallLocal = true)]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[Sync]", "[RPC(MultiplayerAPI.RPCMode.AnyPeer, CallLocal = true)]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[Slave]", "[RPC]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[Puppet]", "[RPC]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[PuppetSync]", "[RPC(CallLocal = true)]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[Master]", "The master and mastersync rpc behavior is not officially supported anymore. Try using another keyword or making custom logic using Multiplayer.GetRemoteSenderId()\n[RPC]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_with_regex("[MasterSync]", "The master and mastersync rpc behavior is not officially supported anymore. Try using another keyword or making custom logic using Multiplayer.GetRemoteSenderId()\n[RPC(CallLocal = true)]", &ProjectConverter3To4::rename_csharp_attributes, "custom rename csharp", reg_container);
	valid = valid && test_conversion_gdscript_builtin("\tif OS.window_resizable: pass", "\tif (not get_window().unresizable): pass", &ProjectConverter3To4::rename_gdscript_functions, "custom rename", reg_container, false);