### 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
return GDScriptLanguage::get_singleton();
}
void GDScript::get_constants(HashMap<StringName, Variant> *p_constants) {
	if (p_constants) {
		for (const KeyValue<StringName, Variant> &E : constants) {
			(*p_constants)[E.key] = E.value;
		}
	}
}
void GDScript::get_members(HashSet<StringName> *p_members) {
	if (p_members) {
		for (const StringName &E : members) {
			p_members->insert(E);
		}
	}
}
const Variant GDScript::get_rpc_config() const {