### 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
if (_base) {
		return Ref<GDScript>(_base);
	} else {
		return Ref<Script>();
	}
}
StringName GDScript::get_global_name() const {
	return name;
}
StringName GDScript::get_instance_base_type() const {
	if (native.is_valid()) {
		return native->get_name();
	}
	if (base.is_valid() && base->is_valid()) {
		return base->get_instance_base_type();
	}
	return StringName();
}
struct _GDScriptMemberSort {
	int index = 0;
	StringName name;
	_FORCE_INLINE_ bool operator<(const _GDScriptMemberSort &p_member) const { return index < p_member.index; }
};
#ifdef TOOLS_ENABLED
void GDScript::_placeholder_erased(PlaceHolderScriptInstance *p_placeholder) {
	placeholders.erase(p_placeholder);
}
#endif
void GDScript::_get_script_method_list(List<MethodInfo> *r_list, bool p_include_base) const {