### 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)
edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("ui_copy"), EDIT_COPY);
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("ui_paste"), EDIT_PASTE);
	edit_menu->get_popup()->add_separator();
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("ui_text_select_all"), EDIT_SELECT_ALL);
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/duplicate_selection"), EDIT_DUPLICATE_SELECTION);
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/duplicate_lines"), EDIT_DUPLICATE_LINES);
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/evaluate_selection"), EDIT_EVALUATE);
	edit_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/toggle_word_wrap"), EDIT_TOGGLE_WORD_WRAP);
	edit_menu->get_popup()->add_separator();
	{
		PopupMenu *sub_menu = memnew(PopupMenu);
		sub_menu->set_name("LineMenu");
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/move_up"), EDIT_MOVE_LINE_UP);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/move_down"), EDIT_MOVE_LINE_DOWN);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/indent"), EDIT_INDENT);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/unindent"), EDIT_UNINDENT);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/delete_line"), EDIT_DELETE_LINE);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/toggle_comment"), EDIT_TOGGLE_COMMENT);
		sub_menu->connect("id_pressed", callable_mp(this, &ScriptTextEditor::_edit_option));
		edit_menu->get_popup()->add_child(sub_menu);
		edit_menu->get_popup()->add_submenu_item(TTR("Line"), "LineMenu");
	}
	{
		PopupMenu *sub_menu = memnew(PopupMenu);
		sub_menu->set_name("FoldingMenu");
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/toggle_fold_line"), EDIT_TOGGLE_FOLD_LINE);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/fold_all_lines"), EDIT_FOLD_ALL_LINES);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/unfold_all_lines"), EDIT_UNFOLD_ALL_LINES);
		sub_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/create_code_region"), EDIT_CREATE_CODE_REGION);
		sub_menu->connect("id_pressed", callable_mp(this, &ScriptTextEditor::_edit_option));