### 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)
code_editor->get_text_editor()->set_gutter_draw(connection_gutter, EDITOR_GET("text_editor/appearance/gutters/show_info_gutter"));
	code_editor->update_editor_settings();
}
bool ScriptTextEditor::is_unsaved() {
	const bool unsaved =
			code_editor->get_text_editor()->get_version() != code_editor->get_text_editor()->get_saved_version() ||
			script->get_path().is_empty(); 
	return unsaved;
}
Variant ScriptTextEditor::get_edit_state() {
	return code_editor->get_edit_state();
}
void ScriptTextEditor::set_edit_state(const Variant &p_state) {
	code_editor->set_edit_state(p_state);
	Dictionary state = p_state;
	if (state.has("syntax_highlighter")) {
		int idx = highlighter_menu->get_item_idx_from_text(state["syntax_highlighter"]);
		if (idx >= 0) {
			_change_syntax_highlighter(idx);
		}
	}
	if (editor_enabled) {
#ifndef ANDROID_ENABLED
		ensure_focus();
#endif
	}
}
Variant ScriptTextEditor::get_navigation_state() {