### 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
#ifdef TOOLS_ENABLED
	HashMap<StringName, Variant>::ConstIterator E = member_default_values_cache.find(p_property);
	if (E) {
		r_value = E->value;
		return true;
	}
	if (base_cache.is_valid()) {
		return base_cache->get_property_default_value(p_property, r_value);
	}
#endif
	return false;
}
ScriptInstance *GDScript::instance_create(Object *p_this) {
	GDScript *top = this;
	while (top->_base) {
		top = top->_base;
	}
	if (top->native.is_valid()) {
		if (!ClassDB::is_parent_class(p_this->get_class_name(), top->native->get_name())) {
			if (EngineDebugger::is_active()) {
				GDScriptLanguage::get_singleton()->debug_break_parse(_get_debug_path(), 1, "Script inherits from native type '" + String(top->native->get_name()) + "', so it can't be assigned to an object of type: '" + p_this->get_class() + "'");
			}
			ERR_FAIL_V_MSG(nullptr, "Script inherits from native type '" + String(top->native->get_name()) + "', so it can't be assigned to an object of type '" + p_this->get_class() + "'" + ".");
		}
	}
	Callable::CallError unchecked_error;
	return _create_instance(nullptr, 0, p_this, Object::cast_to<RefCounted>(p_this) != nullptr, unchecked_error);
}
PlaceHolderScriptInstance *GDScript::placeholder_instance_create(Object *p_this) {