### 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)

}
	if (line.contains("OS.get_real_window_size")) {
		line = line.replace("OS.get_real_window_size", "get_window().get_size_with_decorations");
	}
	if (line.contains("OS.is_window_focused")) {
		line = line.replace("OS.is_window_focused", "get_window().has_focus");
	}
	if (line.contains("OS.move_window_to_foreground")) {
		line = line.replace("OS.move_window_to_foreground", "get_window().move_to_foreground");
	}
	if (line.contains("OS.request_attention")) {
		line = line.replace("OS.request_attention", "get_window().request_attention");
	}
	if (line.contains("OS.set_window_title")) {
		line = line.replace("OS.set_window_title", "get_window().set_title");
	}
	// 
	if (line.contains("get_tree().set_input_as_handled()")) {
		line = line.replace("get_tree().set_input_as_handled()", "get_viewport().set_input_as_handled()");
	}
	// 
	// 
	if (line.contains("_unhandled_key_input(event: InputEventKey)")) {
		line = line.replace("_unhandled_key_input(event: InputEventKey)", "_unhandled_key_input(event: InputEvent)");
	}
	if (line.contains("Engine.editor_hint")) {
		line = line.replace("Engine.editor_hint", "Engine.is_editor_hint()");
	}
}
void ProjectConverter3To4::process_csharp_line(String &line, const RegExContainer &reg_container) {