### 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)

continue;
			} else if (chr == '=') {
				foundNextEqual = true;
				assigned_value = line.right(current_index).strip_edges();
				assigned_value = assigned_value == "true" ? "false" : "true";
			} else {
				break;
			}
		}
		if (foundNextEqual) {
			line = line.substr(0, start) + "ignore_rotation =" + assigned_value + " # reversed \"rotating\" for Camera2D";
		}
	}
	// 
	if (line.contains("OS.get_ticks_msec")) {
		line = line.replace("OS.get_ticks_msec", "Time.get_ticks_msec");
	}
	if (line.contains("OS.get_ticks_usec")) {
		line = line.replace("OS.get_ticks_usec", "Time.get_ticks_usec");
	}
	if (line.contains("OS.get_unix_time")) {
		line = line.replace("OS.get_unix_time", "Time.get_unix_time_from_system");
	}
	if (line.contains("OS.get_datetime")) {
		line = line.replace("OS.get_datetime", "Time.get_datetime_dict_from_system");
	}
	// 
	if (line.contains("OS.get_display_cutouts")) {
		line = line.replace("OS.get_display_cutouts", "DisplayServer.get_display_cutouts");
	}