### 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)
} break;
		case EDIT_DUPLICATE_LINES: {
			code_editor->get_text_editor()->duplicate_lines();
		} break;
		case EDIT_TOGGLE_FOLD_LINE: {
			int previous_line = -1;
			for (int caret_idx : tx->get_caret_index_edit_order()) {
				int line_idx = tx->get_caret_line(caret_idx);
				if (line_idx != previous_line) {
					tx->toggle_foldable_line(line_idx);
					previous_line = line_idx;
				}
			}
			tx->queue_redraw();
		} break;
		case EDIT_FOLD_ALL_LINES: {
			tx->fold_all_lines();
			tx->queue_redraw();
		} break;
		case EDIT_UNFOLD_ALL_LINES: {
			tx->unfold_all_lines();
			tx->queue_redraw();
		} break;
		case EDIT_CREATE_CODE_REGION: {
			tx->create_code_region();
		} break;
		case EDIT_TOGGLE_COMMENT: {
			_edit_option_toggle_inline_comment();
		} break;
		case EDIT_COMPLETE: {