### 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)
default_layout->set_value(docks_section, "dock_4", "FileSystem");
	default_layout->set_value(docks_section, "dock_5", "Inspector,Node,History");
	for (int i = 0; i < vsplits.size(); i++) {
		default_layout->set_value(docks_section, "dock_split_" + itos(i + 1), 0);
	}
	default_layout->set_value(docks_section, "dock_hsplit_1", 0);
	default_layout->set_value(docks_section, "dock_hsplit_2", 270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_3", -270 * EDSCALE);
	default_layout->set_value(docks_section, "dock_hsplit_4", 0);
	_update_layouts_menu();
	
	bottom_panel = memnew(PanelContainer);
	bottom_panel->add_theme_style_override("panel", theme->get_stylebox(SNAME("BottomPanel"), EditorStringName(EditorStyles)));
	center_split->add_child(bottom_panel);
	center_split->set_dragger_visibility(SplitContainer::DRAGGER_HIDDEN);
	bottom_panel_vb = memnew(VBoxContainer);
	bottom_panel->add_child(bottom_panel_vb);
	bottom_panel_hb = memnew(HBoxContainer);
	bottom_panel_hb->set_custom_minimum_size(Size2(0, 24 * EDSCALE)); 
	bottom_panel_vb->add_child(bottom_panel_hb);
	bottom_panel_hb_editors = memnew(HBoxContainer);
	bottom_panel_hb_editors->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	bottom_panel_hb->add_child(bottom_panel_hb_editors);
	editor_toaster = memnew(EditorToaster);
	bottom_panel_hb->add_child(editor_toaster);
	VBoxContainer *version_info_vbc = memnew(VBoxContainer);
	bottom_panel_hb->add_child(version_info_vbc);
	
	Control *v_spacer = memnew(Control);
	version_info_vbc->add_child(v_spacer);