### 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)
has_color = false;
					}
				} break;
				default:
					has_color = false;
					break;
			}
			if (has_color) {
				color_panel->set_position(get_screen_position() + local_pos);
			}
		}
		_make_context_menu(tx->has_selection(), has_color, foldable, open_docs, goto_definition, local_pos);
	}
}
void ScriptTextEditor::_color_changed(const Color &p_color) {
	String new_args;
	if (p_color.a == 1.0f) {
		new_args = String("(" + rtos(p_color.r) + ", " + rtos(p_color.g) + ", " + rtos(p_color.b) + ")");
	} else {
		new_args = String("(" + rtos(p_color.r) + ", " + rtos(p_color.g) + ", " + rtos(p_color.b) + ", " + rtos(p_color.a) + ")");
	}
	String line = code_editor->get_text_editor()->get_line(color_position.x);
	String line_with_replaced_args = line.replace(color_args, new_args);
	color_args = new_args;
	code_editor->get_text_editor()->begin_complex_operation();
	code_editor->get_text_editor()->set_line(color_position.x, line_with_replaced_args);
	code_editor->get_text_editor()->end_complex_operation();
	code_editor->get_text_editor()->queue_redraw();
}
void ScriptTextEditor::_prepare_edit_menu() {