### 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)
ERR_FAIL_COND_V_MSG(err != OK, false, "Error saving new docs:" + itos(err));
		print_line("Deleting docs cache...");
		if (FileAccess::exists(EditorHelp::get_cache_full_path())) {
			DirAccess::remove_file_or_error(EditorHelp::get_cache_full_path());
		}
		OS::get_singleton()->set_exit_code(EXIT_SUCCESS);
		return false;
	}
	if (dump_gdextension_interface) {
		GDExtensionInterfaceDump::generate_gdextension_interface_file("gdextension_interface.h");
	}
	if (dump_extension_api) {
		Engine::get_singleton()->set_editor_hint(true); /
		GDExtensionAPIDump::generate_extension_json_file("extension_api.json", include_docs_in_extension_api_dump);
	}
	if (dump_gdextension_interface || dump_extension_api) {
		OS::get_singleton()->set_exit_code(EXIT_SUCCESS);
		return false;
	}
	if (validate_extension_api) {
		bool valid = GDExtensionAPIDump::validate_extension_json_file(validate_extension_api_file) == OK;
		OS::get_singleton()->set_exit_code(valid ? EXIT_SUCCESS : EXIT_FAILURE);
		return false;
	}
#ifndef DISABLE_DEPRECATED
	if (converting_project) {
		int ret = ProjectConverter3To4(converter_max_kb_file, converter_max_line_length).convert();
		if (ret) {
			OS::get_singleton()->set_exit_code(EXIT_SUCCESS);
		}