### 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)

// 
		line = reg_container.reg_os_set_borderless.sub(line, "get_window().borderless = ($1)", true);
		// 
		line = reg_container.reg_os_get_borderless.sub(line, "get_window().borderless", true);
	}
	// 
	if (line.contains("OS.SCREEN_ORIENTATION_")) {
		line = reg_container.reg_os_screen_orient_enum.sub(line, "DisplayServer.SCREEN_$1", true);
	}
	// 
	if (line.contains("current_screen")) {
		line = reg_container.reg_os_current_screen.sub(line, "get_window().$1current_screen", true);
	}
	if (line.contains("min_window_size")) {
		line = reg_container.reg_os_min_window_size.sub(line, "get_window().$1min_size", true);
	}
	if (line.contains("max_window_size")) {
		line = reg_container.reg_os_max_window_size.sub(line, "get_window().$1max_size", true);
	}
	if (line.contains("window_position")) {
		line = reg_container.reg_os_window_position.sub(line, "get_window().$1position", true);
	}
	if (line.contains("window_size")) {
		line = reg_container.reg_os_window_size.sub(line, "get_window().$1size", true);
	}
	if (line.contains("et_screen_orientation")) {
		line = reg_container.reg_os_getset_screen_orient.sub(line, "DisplayServer.screen_$1et_orientation", true);
	}
	// 
	if (contains_function_call(line, "instance")) {