### 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)
}
						
						for (const Connection &E2 : E.value.connections_from) {
							Connection conn = E2;
							bool valid = modifiable_node->has_method(conn.callable.get_method()) || Ref<Script>(modifiable_node->get_script()).is_null() || Ref<Script>(modifiable_node->get_script())->has_method(conn.callable.get_method());
							ERR_CONTINUE_MSG(!valid, vformat("Attempt to connect signal '%s.%s' to nonexistent method '%s.%s'.", conn.signal.get_object()->get_class(), conn.signal.get_name(), conn.callable.get_object()->get_class(), conn.callable.get_method()));
							
							Object *source_object = conn.signal.get_object();
							if (source_object) {
								ERR_FAIL_COND(source_object->connect(conn.signal.get_name(), Callable(modifiable_node, conn.callable.get_method()), conn.flags) != OK);
							}
						}
						
						for (const Node::GroupInfo &E2 : E.value.groups) {
							modifiable_node->add_to_group(E2.name, E2.persistent);
						}
					}
				}
			}
			
			editor_history.cleanup_history();
			_notify_scene_updated(current_edited_scene);
		}
		edited_scene_map.clear();
	}
	editor_data.set_edited_scene(original_edited_scene_idx);
	_edit_current();
}
int EditorNode::plugin_init_callback_count = 0;
void EditorNode::add_plugin_init_callback(EditorPluginInitializeCallback p_callback) {