### 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)
*
 * The OS implementation can impact its draw step with the Main::force_redraw() method.
 */
uint64_t Main::last_ticks = 0;
uint32_t Main::frames = 0;
uint32_t Main::hide_print_fps_attempts = 3;
uint32_t Main::frame = 0;
bool Main::force_redraw_requested = false;
int Main::iterating = 0;
bool Main::agile_input_event_flushing = false;
bool Main::is_iterating() {
	return iterating > 0;
}
/
static uint64_t physics_process_max = 0;
static uint64_t process_max = 0;
static uint64_t navigation_process_max = 0;
bool Main::iteration() {
	/
	/
	iterating++;
	const uint64_t ticks = OS::get_singleton()->get_ticks_usec();
	Engine::get_singleton()->_frame_ticks = ticks;
	main_timer_sync.set_cpu_ticks_usec(ticks);
	main_timer_sync.set_fixed_fps(fixed_fps);
	const uint64_t ticks_elapsed = ticks - last_ticks;
	const int physics_ticks_per_second = Engine::get_singleton()->get_physics_ticks_per_second();
	const double physics_step = 1.0 / physics_ticks_per_second;
	const double time_scale = Engine::get_singleton()->get_time_scale();
	MainFrameTime advance = main_timer_sync.advance(physics_step, physics_ticks_per_second);