### 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)
window_flags |= DisplayServer::WINDOW_FLAG_RESIZE_DISABLED_BIT;
		}
		if (bool(GLOBAL_GET("display/window/size/borderless"))) {
			window_flags |= DisplayServer::WINDOW_FLAG_BORDERLESS_BIT;
		}
		if (bool(GLOBAL_GET("display/window/size/always_on_top"))) {
			window_flags |= DisplayServer::WINDOW_FLAG_ALWAYS_ON_TOP_BIT;
		}
		if (bool(GLOBAL_GET("display/window/size/transparent"))) {
			window_flags |= DisplayServer::WINDOW_FLAG_TRANSPARENT_BIT;
		}
		if (bool(GLOBAL_GET("display/window/size/extend_to_title"))) {
			window_flags |= DisplayServer::WINDOW_FLAG_EXTEND_TO_TITLE_BIT;
		}
		if (bool(GLOBAL_GET("display/window/size/no_focus"))) {
			window_flags |= DisplayServer::WINDOW_FLAG_NO_FOCUS_BIT;
		}
		window_mode = (DisplayServer::WindowMode)(GLOBAL_GET("display/window/size/mode").operator int());
		int initial_position_type = GLOBAL_GET("display/window/size/initial_position_type").operator int();
		if (initial_position_type == 0) { 
			if (!init_use_custom_pos) {
				init_custom_pos = GLOBAL_GET("display/window/size/initial_position").operator Vector2i();
				init_use_custom_pos = true;
			}
		} else if (initial_position_type == 1) { 
			if (!init_use_custom_screen) {
				init_screen = DisplayServer::SCREEN_PRIMARY;
				init_use_custom_screen = true;
			}
		} else if (initial_position_type == 2) {