### 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 (old_line.size() > 1000) {
		old_line = old_line.substr(0, 997) + "...";
	}
	if (new_line.size() > 1000) {
		new_line = new_line.substr(0, 997) + "...";
	}
	old_line = old_line.replace("\r", "").replace("\n", "").strip_edges();
	new_line = new_line.replace("\r", "").replace("\n", "").strip_edges();
	return vformat("Line (%d) - FULL LINES - \"\"\" %s \"\"\"  =====>  \"\"\" %s \"\"\"", current_line, old_line, new_line);
}
// Collects string from vector strings
String ProjectConverter3To4::collect_string_from_vector(Vector<SourceLine> &vector) {
	String string = "";
	for (int i = 0; i < vector.size(); i++) {
		string += vector[i].line;
		if (i != vector.size() - 1) {
			string += "\n";
		}
	}
	return string;
}
#endif // 
#endif //