### 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)
OS::get_singleton()->print("  --path <directory>                Path to a project (<directory> must contain a 'project.godot' file).\n");
	OS::get_singleton()->print("  -u, --upwards                     Scan folders upwards for project.godot file.\n");
	OS::get_singleton()->print("  --main-pack <file>                Path to a pack (.pck) file to load.\n");
	OS::get_singleton()->print("  --render-thread <mode>            Render thread mode ['unsafe', 'safe', 'separate'].\n");
	OS::get_singleton()->print("  --remote-fs <address>             Remote filesystem (<host/IP>[:<port>] address).\n");
	OS::get_singleton()->print("  --remote-fs-password <password>   Password for remote filesystem.\n");
	OS::get_singleton()->print("  --audio-driver <driver>           Audio driver [");
	for (int i = 0; i < AudioDriverManager::get_driver_count(); i++) {
		if (i > 0) {
			OS::get_singleton()->print(", ");
		}
		OS::get_singleton()->print("'%s'", AudioDriverManager::get_driver(i)->get_name());
	}
	OS::get_singleton()->print("].\n");
	OS::get_singleton()->print("  --display-driver <driver>         Display driver (and rendering driver) [");
	for (int i = 0; i < DisplayServer::get_create_function_count(); i++) {
		if (i > 0) {
			OS::get_singleton()->print(", ");
		}
		OS::get_singleton()->print("'%s' (", DisplayServer::get_create_function_name(i));
		Vector<String> rd = DisplayServer::get_create_function_rendering_drivers(i);
		for (int j = 0; j < rd.size(); j++) {
			if (j > 0) {
				OS::get_singleton()->print(", ");
			}
			OS::get_singleton()->print("'%s'", rd[j].utf8().get_data());
		}
		OS::get_singleton()->print(")");
	}
	OS::get_singleton()->print("].\n");