### 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)
#endif
	settings_menu->add_item(TTR("Manage Editor Features..."), SETTINGS_MANAGE_FEATURE_PROFILES);
#ifndef ANDROID_ENABLED
	settings_menu->add_item(TTR("Manage Export Templates..."), SETTINGS_MANAGE_EXPORT_TEMPLATES);
#endif
#if !defined(ANDROID_ENABLED) && !defined(WEB_ENABLED)
	settings_menu->add_item(TTR("Configure FBX Importer..."), SETTINGS_MANAGE_FBX_IMPORTER);
#endif
	help_menu = memnew(PopupMenu);
	help_menu->set_name(TTR("Help"));
	main_menu->add_child(help_menu);
	help_menu->connect("id_pressed", callable_mp(this, &EditorNode::_menu_option));
	ED_SHORTCUT_AND_COMMAND("editor/editor_help", TTR("Search Help"), Key::F1);
	ED_SHORTCUT_OVERRIDE("editor/editor_help", "macos", KeyModifierMask::ALT | Key::SPACE);
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("HelpSearch"), EditorStringName(EditorIcons)), ED_GET_SHORTCUT("editor/editor_help"), HELP_SEARCH);
	help_menu->add_separator();
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/online_docs", TTR("Online Documentation")), HELP_DOCS);
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/q&a", TTR("Questions & Answers")), HELP_QA);
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/community", TTR("Community")), HELP_COMMUNITY);
	help_menu->add_separator();
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ActionCopy"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/copy_system_info", TTR("Copy System Info")), HELP_COPY_SYSTEM_INFO);
	help_menu->set_item_tooltip(-1, TTR("Copies the system info as a single-line text into the clipboard."));
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/report_a_bug", TTR("Report a Bug")), HELP_REPORT_A_BUG);
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/suggest_a_feature", TTR("Suggest a Feature")), HELP_SUGGEST_A_FEATURE);
	help_menu->add_icon_shortcut(theme->get_icon(SNAME("ExternalLink"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/send_docs_feedback", TTR("Send Docs Feedback")), HELP_SEND_DOCS_FEEDBACK);
	help_menu->add_separator();
	if (!global_menu || !OS::get_singleton()->has_feature("macos")) {
		
		help_menu->add_icon_shortcut(theme->get_icon(SNAME("Godot"), EditorStringName(EditorIcons)), ED_SHORTCUT_AND_COMMAND("editor/about", TTR("About Godot")), HELP_ABOUT);
	}