### 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 (globals.has(p_name)) {
		
		global_array.write[globals[p_name]] = p_value;
		return;
	}
	globals[p_name] = global_array.size();
	global_array.push_back(p_value);
	_global_array = global_array.ptrw();
}
void GDScriptLanguage::add_global_constant(const StringName &p_variable, const Variant &p_value) {
	_add_global(p_variable, p_value);
}
void GDScriptLanguage::add_named_global_constant(const StringName &p_name, const Variant &p_value) {
	named_globals[p_name] = p_value;
}
Variant GDScriptLanguage::get_any_global_constant(const StringName &p_name) {
	if (named_globals.has(p_name)) {
		return named_globals[p_name];
	}
	if (globals.has(p_name)) {
		return _global_array[globals[p_name]];
	}
	ERR_FAIL_V_MSG(Variant(), vformat("Could not find any global constant with name: %s.", p_name));
}
void GDScriptLanguage::remove_named_global_constant(const StringName &p_name) {
	ERR_FAIL_COND(!named_globals.has(p_name));
	named_globals.erase(p_name);
}
void GDScriptLanguage::init() {