### 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)
Dictionary floating_docks_dump = p_layout->get_value(p_section, "dock_floating", Dictionary());
	bool restore_window_on_load = EDITOR_GET("interface/multi_window/restore_windows_on_load");
	for (int i = 0; i < DOCK_SLOT_MAX; i++) {
		if (!p_layout->has_section_key(p_section, "dock_" + itos(i + 1))) {
			continue;
		}
		Vector<String> names = String(p_layout->get_value(p_section, "dock_" + itos(i + 1))).split(",");
		for (int j = names.size() - 1; j >= 0; j--) {
			String name = names[j];
			
			int atidx = -1;
			Control *node = nullptr;
			for (int k = 0; k < DOCK_SLOT_MAX; k++) {
				if (!dock_slot[k]->has_node(name)) {
					continue;
				}
				node = Object::cast_to<Control>(dock_slot[k]->get_node(name));
				if (!node) {
					continue;
				}
				atidx = k;
				break;
			}
			if (atidx == -1) {