### 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;
	Vector<String> names = Vector<String>();
	for (unsigned int current_index = 0; p_array[current_index][0]; current_index++) {
		String name_3_x = p_array[current_index][0];
		String name_4_0 = p_array[current_index][1];
		if (name_3_x != name_3_x.strip_edges()) {
			ERR_PRINT(vformat("Invalid Entry \"%s\" contains leading or trailing spaces.", name_3_x));
			valid = false;
		}
		if (names.has(name_3_x)) {
			ERR_PRINT(vformat("Found duplicated entry, pair ( -> %s , %s)", name_3_x, name_4_0));
			valid = false;
		}
		names.append(name_3_x);
		if (name_4_0 != name_4_0.strip_edges()) {
			ERR_PRINT(vformat("Invalid Entry \"%s\" contains leading or trailing spaces.", name_3_x));
			valid = false;
		}
		if (names.has(name_4_0)) {
			ERR_PRINT(vformat("Found duplicated entry, pair ( -> %s , %s)", name_3_x, name_4_0));
			valid = false;
		}
		if (!p_ignore_4_0_name) {
			names.append(name_4_0);
		}
	}
	return valid;
};
Vector<String> ProjectConverter3To4::parse_arguments(const String &line) {