### 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)
if (connection_target_node) {
				
				if (!c.callable.is_custom()) {
					ConnectionWithNodePath connection_to;
					connection_to.connection = c;
					connection_to.node_path = p_node->get_path_to(connection_target_node);
					valid_connections_to.push_back(connection_to);
				}
			}
		}
		
		List<Connection> connections_from;
		p_node->get_signals_connected_to_this(&connections_from);
		List<Connection> valid_connections_from;
		for (const Connection &c : connections_from) {
			Node *source_node = Object::cast_to<Node>(c.signal.get_object());
			Node *valid_source_owner = nullptr;
			if (source_node) {
				valid_source_owner = source_node->get_owner();
				while (valid_source_owner) {
					if (valid_source_owner == p_root) {
						break;
					}
					valid_source_owner = valid_source_owner->get_owner();
				}
			}
			if (!source_node || valid_source_owner == nullptr) {
				
				if (!c.callable.is_custom()) {
					valid_connections_from.push_back(c);