### 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)
List<String> property_names;
						for (const PropertyInfo &E2 : pinfo) {
							if (E2.usage & PROPERTY_USAGE_STORAGE) {
								property_names.push_back(E2.name);
							}
						}
						
						for (const KeyValue<StringName, Variant> &E2 : E.value.property_table) {
							if (property_names.find(E2.key)) {
								modifiable_node->set(E2.key, E2.value);
							}
						}
						
						for (const ConnectionWithNodePath &E2 : E.value.connections_to) {
							Connection conn = E2.connection;
							
							Node *target_node = cast_to<Node>(conn.callable.get_object());
							
							
							
							if (!target_node || !target_node->is_queued_for_deletion()) {
								target_node = modifiable_node->get_node_or_null(E2.node_path);
							}
							if (target_node) {
								
								Callable new_callable = Callable(target_node, conn.callable.get_method());
								if (!modifiable_node->is_connected(conn.signal.get_name(), new_callable)) {
									ERR_FAIL_COND(modifiable_node->connect(conn.signal.get_name(), new_callable, conn.flags) != OK);
								}
							}