### 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)
String word_at_pos = tx->get_word_at_pos(local_pos);
		if (word_at_pos.is_empty()) {
			word_at_pos = tx->get_word_under_caret(caret_clicked);
		}
		if (word_at_pos.is_empty()) {
			word_at_pos = tx->get_selected_text(caret_clicked);
		}
		bool has_color = (word_at_pos == "Color");
		bool foldable = tx->can_fold_line(row) || tx->is_line_folded(row);
		bool open_docs = false;
		bool goto_definition = false;
		if (ScriptServer::is_global_class(word_at_pos) || word_at_pos.is_resource_file()) {
			open_docs = true;
		} else {
			Node *base = get_tree()->get_edited_scene_root();
			if (base) {
				base = _find_node_for_script(base, base, script);
			}
			ScriptLanguage::LookupResult result;
			if (script->get_language()->lookup_code(tx->get_text_for_symbol_lookup(), word_at_pos, script->get_path(), base, result) == OK) {
				open_docs = true;
			}
		}
		if (has_color) {
			String line = tx->get_line(row);
			color_position.x = row;
			color_position.y = col;
			int begin = -1;
			int end = -1;
			enum EXPRESSION_PATTERNS {