### 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_CONVERT_INDENT_TO_SPACES: {
			tx->set_indent_using_spaces(true);
			convert_indent();
		} break;
		case EDIT_CONVERT_INDENT_TO_TABS: {
			tx->set_indent_using_spaces(false);
			convert_indent();
		} break;
		case EDIT_PICK_COLOR: {
			color_panel->popup();
		} break;
		case EDIT_TO_UPPERCASE: {
			_convert_case(CodeTextEditor::UPPER);
		} break;
		case EDIT_TO_LOWERCASE: {
			_convert_case(CodeTextEditor::LOWER);
		} break;
		case EDIT_CAPITALIZE: {
			_convert_case(CodeTextEditor::CAPITALIZE);
		} break;
		case EDIT_EVALUATE: {
			Expression expression;
			tx->begin_complex_operation();
			for (int caret_idx = 0; caret_idx < tx->get_caret_count(); caret_idx++) {
				Vector<String> lines = tx->get_selected_text(caret_idx).split("\n");
				PackedStringArray results;
				for (int i = 0; i < lines.size(); i++) {
					String line = lines[i];
					String whitespace = line.substr(0, line.size() - line.strip_edges(true, false).size());