### 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)
print_line(String(VERSION_NAME) + " v" + get_full_version_string() + " - " + String(VERSION_WEBSITE));
	OS::get_singleton()->print("Free and open source software under the terms of the MIT license.\n");
	OS::get_singleton()->print("(c) 2014-present Godot Engine contributors.\n");
	OS::get_singleton()->print("(c) 2007-2014 Juan Linietsky, Ariel Manzur.\n");
	OS::get_singleton()->print("\n");
	OS::get_singleton()->print("Usage: %s [options] [path to scene or 'project.godot' file]\n", p_binary);
	OS::get_singleton()->print("\n");
	OS::get_singleton()->print("General options:\n");
	OS::get_singleton()->print("  -h, --help                        Display this help message.\n");
	OS::get_singleton()->print("  --version                         Display the version string.\n");
	OS::get_singleton()->print("  -v, --verbose                     Use verbose stdout mode.\n");
	OS::get_singleton()->print("  -q, --quiet                       Quiet mode, silences stdout messages. Errors are still displayed.\n");
	OS::get_singleton()->print("\n");
	OS::get_singleton()->print("Run options:\n");
	OS::get_singleton()->print("  --, ++                            Separator for user-provided arguments. Following arguments are not used by the engine, but can be read from `OS.get_cmdline_user_args()`.\n");
#ifdef TOOLS_ENABLED
	OS::get_singleton()->print("  -e, --editor                      Start the editor instead of running the scene.\n");
	OS::get_singleton()->print("  -p, --project-manager             Start the project manager, even if a project is auto-detected.\n");
	OS::get_singleton()->print("  --debug-server <uri>              Start the editor debug server (<protocol>://<host/IP>[:<port>], e.g. tcp://127.0.0.1:6007)\n");
#if defined(MODULE_GDSCRIPT_ENABLED) && !defined(GDSCRIPT_NO_LSP)
	OS::get_singleton()->print("  --lsp-port <port>                 Use the specified port for the language server protocol. The port must be between 0 to 65535.\n");
#endif 
#endif 
	OS::get_singleton()->print("  --quit                            Quit after the first iteration.\n");
	OS::get_singleton()->print("  --quit-after <int>                Quit after the given number of iterations. Set to 0 to disable.\n");
	OS::get_singleton()->print("  -l, --language <locale>           Use a specific locale (<locale> being a two-letter code).\n");