### Godot version

4.1.3

### System information

Linux

### Issue description

I'm trying to make an editor plugin on Rust:

```rust
#[derive(GodotClass)]
#[class(tool, editor_plugin, init, base=EditorPlugin)]
pub struct MyEditorPluginBase {}
```

But due to some limitations, I still have to use GDScript for some specific things.

So I tried to make a subclass of this Rust class:

```gdscript
@tool
class_name MyEditorPlugin
extends MyEditorPluginBase
```

This would work if `MyEditorPluginBase` was a GDScript class, but since it's a GDExtension class in my case, it doesn't work:

> Unable to load addon script from path: 'res://addons/my_addon/my_editor_plugin.gd' Base type is not EditorPlugin.

But it obviously **IS** EditorPlugin!

![godot-editorplugin-docs](https://github.com/godotengine/godot/assets/3236464/4665deeb-30f0-45cd-bfff-56101b9d4875)

![godot-editorplugin](https://github.com/godotengine/godot/assets/3236464/b1b6ecb4-de22-4abd-91a3-e180691f67ee)

If I understand correctly, this behavior is caused by this function, which checks some mysterious "instance base type" instead of real inheritance:

https://github.com/godotengine/godot/blob/fa4a65387ea41506ecc519fc61a06da110dce51c/editor/editor_node.cpp#L3456-L3458

https://github.com/godotengine/godot/blob/fa4a65387ea41506ecc519fc61a06da110dce51c/modules/gdscript/gdscript.cpp#L260-L263

Since the [documentation](https://docs.godotengine.org/en/stable/tutorials/plugins/editor/making_plugins.html#the-script-file) doesn't say that the script must be a **direct** subclass of EditorPlugin (and an indirect subclass works fine in GDScript), I interpret this behavior as a Godot bug.

### Steps to reproduce

See above

### Minimal reproduction project

[gdext_editor_plugin_test.zip](https://github.com/godotengine/godot/files/13451014/gdext_editor_plugin_test.zip)
if (!p_is_generating) {
			result.passed = check_output(result.output);
		}
		return result;
	}
	
	if (source_file.match("*.notest.gd")) {
		enable_stdout();
		result.passed = check_output(result.output);
		return result;
	}
	
	const HashMap<StringName, GDScriptFunction *>::ConstIterator test_function_element = script->get_member_functions().find(GDScriptTestRunner::test_function_name);
	if (!test_function_element) {
		enable_stdout();
		result.status = GDTEST_LOAD_ERROR;
		result.output = "";
		result.passed = false;
		ERR_FAIL_V_MSG(result, "\nCould not find test function on: '" + source_file + "'");
	}
	
	ErrorHandlerData error_data(&result, this);
	_print_handler.userdata = &result;
	_error_handler.userdata = &error_data;
	add_print_handler(&_print_handler);
	add_error_handler(&_error_handler);
	script->reload();
	
	Object *obj = ClassDB::instantiate(script->get_native()->get_name());
	Ref<RefCounted> obj_ref;