### Godot version

4.1.dev

### System information

Win11

### Issue description

I load a non-existing GDScript, but it still returns a valid instance instead of null.
```gdscript
@tool
extends EditorScript

func _run():
	var s = ResourceLoader.load("non_exists.gd", "", ResourceLoader.CACHE_MODE_IGNORE)
	print(s)
	assert(s == null)

```

```
  Attempt to open script 'res://non_exists.gd' resulted in error 'File not found'.
<GDScript#-9223369015982753437>
  res://new_script.gd:7 - Assertion failed.

```

### Steps to reproduce

N/A

### Minimal reproduction project

N/A
} break;
			case FULLY_SOLVED: {
				return result;
			}
		}
		if (result != OK) {
			return result;
		}
	}
	return result;
}
void GDScriptParserRef::clear() {
	if (cleared) {
		return;
	}
	cleared = true;
	if (parser != nullptr) {
		memdelete(parser);
	}
	if (analyzer != nullptr) {
		memdelete(analyzer);
	}
}
GDScriptParserRef::~GDScriptParserRef() {
	clear();
	MutexLock lock(GDScriptCache::singleton->mutex);
	GDScriptCache::singleton->parser_map.erase(path);
}
GDScriptCache *GDScriptCache::singleton = nullptr;
void GDScriptCache::move_script(const String &p_from, const String &p_to) {