### 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)
(local_game_path.size() > 1) && (local_game_path[0] == '/' || local_game_path[1] == ':');
				if (!absolute) {
					if (ProjectSettings::get_singleton()->is_using_datapack()) {
						local_game_path = "res://" + local_game_path;
					} else {
						int sep = local_game_path.rfind("/");
						if (sep == -1) {
							Ref<DirAccess> da = DirAccess::create(DirAccess::ACCESS_FILESYSTEM);
							ERR_FAIL_COND_V(da.is_null(), false);
							local_game_path = da->get_current_dir().path_join(local_game_path);
						} else {
							Ref<DirAccess> da = DirAccess::open(local_game_path.substr(0, sep));
							if (da.is_valid()) {
								local_game_path = da->get_current_dir().path_join(
										local_game_path.substr(sep + 1, local_game_path.length()));
							}
						}
					}
				}
			}
			local_game_path = ProjectSettings::get_singleton()->localize_path(local_game_path);
#ifdef TOOLS_ENABLED
			if (editor) {
				if (game_path != String(GLOBAL_GET("application/run/main_scene")) || !editor_node->has_scenes_in_session()) {
					Error serr = editor_node->load_scene(local_game_path);
					if (serr != OK) {
						ERR_PRINT("Failed to load scene");
					}
				}
				DisplayServer::get_singleton()->set_context(DisplayServer::CONTEXT_EDITOR);