### 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)
EditorFileSystem *efs = memnew(EditorFileSystem);
	add_child(efs);
	
	FileDialog::get_icon_func = _file_dialog_get_icon;
	FileDialog::register_func = _file_dialog_register;
	FileDialog::unregister_func = _file_dialog_unregister;
	EditorFileDialog::get_icon_func = _file_dialog_get_icon;
	EditorFileDialog::register_func = _editor_file_dialog_register;
	EditorFileDialog::unregister_func = _editor_file_dialog_unregister;
	editor_export = memnew(EditorExport);
	add_child(editor_export);
	
	EditorColorMap::create();
	EditorTheme::initialize();
	theme = create_custom_theme();
	DisplayServer::set_early_window_clear_color_override(true, theme->get_color(SNAME("background"), EditorStringName(Editor)));
	register_exporters();
	EDITOR_DEF("interface/editor/save_on_focus_loss", false);
	EDITOR_DEF("interface/editor/show_update_spinner", false);
	EDITOR_DEF("interface/editor/update_continuously", false);
	EDITOR_DEF("interface/editor/localize_settings", true);
	EDITOR_DEF_RST("interface/scene_tabs/restore_scenes_on_load", true);
	EDITOR_DEF_RST("interface/inspector/default_property_name_style", EditorPropertyNameProcessor::STYLE_CAPITALIZED);
	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::INT, "interface/inspector/default_property_name_style", PROPERTY_HINT_ENUM, "Raw,Capitalized,Localized"));
	EDITOR_DEF_RST("interface/inspector/default_float_step", 0.001);
	
	
	EditorSettings::get_singleton()->add_property_hint(PropertyInfo(Variant::FLOAT, "interface/inspector/default_float_step", PROPERTY_HINT_RANGE, "0.0000001,1,0.0000001"));
	EDITOR_DEF_RST("interface/inspector/disable_folding", false);
	EDITOR_DEF_RST("interface/inspector/auto_unfold_foreign_scenes", true);