### 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)
/
			DisplayServer::get_singleton()->window_set_title(vformat("%s (DEBUG)", appname));
#else
			DisplayServer::get_singleton()->window_set_title(appname);
#endif
			bool snap_controls = GLOBAL_GET("gui/common/snap_controls_to_pixels");
			sml->get_root()->set_snap_controls_to_pixels(snap_controls);
			bool font_oversampling = GLOBAL_GET("gui/fonts/dynamic_fonts/use_oversampling");
			sml->get_root()->set_use_font_oversampling(font_oversampling);
			int texture_filter = GLOBAL_GET("rendering/textures/canvas_textures/default_texture_filter");
			int texture_repeat = GLOBAL_GET("rendering/textures/canvas_textures/default_texture_repeat");
			sml->get_root()->set_default_canvas_item_texture_filter(
					Viewport::DefaultCanvasItemTextureFilter(texture_filter));
			sml->get_root()->set_default_canvas_item_texture_repeat(
					Viewport::DefaultCanvasItemTextureRepeat(texture_repeat));
		}
#ifdef TOOLS_ENABLED
		if (editor) {
			bool editor_embed_subwindows = EditorSettings::get_singleton()->get_setting(
					"interface/editor/single_window_mode");
			if (editor_embed_subwindows) {
				sml->get_root()->set_embedding_subwindows(true);
			}
		}
#endif
		String local_game_path;
		if (!game_path.is_empty() && !project_manager) {
			local_game_path = game_path.replace("\\", "/");
			if (!local_game_path.begins_with("res://")) {
				bool absolute =