### 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
Object *obj = p_variant;
	if (obj == nullptr || obj->get_instance_id().is_null()) {
		return nullptr;
	}
	return Object::cast_to<GDScript>(obj);
}
void GDScript::_get_dependencies(RBSet<GDScript *> &p_dependencies, const GDScript *p_except) {
	if (p_dependencies.has(this)) {
		return;
	}
	p_dependencies.insert(this);
	for (const KeyValue<StringName, GDScriptFunction *> &E : member_functions) {
		if (E.value == nullptr) {
			continue;
		}
		for (const Variant &V : E.value->constants) {
			GDScript *scr = _get_gdscript_from_variant(V);
			if (scr != nullptr && scr != p_except) {
				scr->_get_dependencies(p_dependencies, p_except);
			}
		}
	}
	if (implicit_initializer) {
		for (const Variant &V : implicit_initializer->constants) {
			GDScript *scr = _get_gdscript_from_variant(V);
			if (scr != nullptr && scr != p_except) {
				scr->_get_dependencies(p_dependencies, p_except);
			}
		}