### 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)
ED_SHORTCUT("script_text_editor/auto_indent", TTR("Auto Indent"), KeyModifierMask::CMD_OR_CTRL | Key::I);
	ED_SHORTCUT_AND_COMMAND("script_text_editor/find", TTR("Find..."), KeyModifierMask::CMD_OR_CTRL | Key::F);
	ED_SHORTCUT("script_text_editor/find_next", TTR("Find Next"), Key::F3);
	ED_SHORTCUT_OVERRIDE("script_text_editor/find_next", "macos", KeyModifierMask::META | Key::G);
	ED_SHORTCUT("script_text_editor/find_previous", TTR("Find Previous"), KeyModifierMask::SHIFT | Key::F3);
	ED_SHORTCUT_OVERRIDE("script_text_editor/find_previous", "macos", KeyModifierMask::META | KeyModifierMask::SHIFT | Key::G);
	ED_SHORTCUT_AND_COMMAND("script_text_editor/replace", TTR("Replace..."), KeyModifierMask::CTRL | Key::R);
	ED_SHORTCUT_OVERRIDE("script_text_editor/replace", "macos", KeyModifierMask::ALT | KeyModifierMask::META | Key::F);
	ED_SHORTCUT("script_text_editor/find_in_files", TTR("Find in Files..."), KeyModifierMask::CMD_OR_CTRL | KeyModifierMask::SHIFT | Key::F);
	ED_SHORTCUT("script_text_editor/replace_in_files", TTR("Replace in Files..."), KeyModifierMask::CMD_OR_CTRL | KeyModifierMask::SHIFT | Key::R);
	ED_SHORTCUT("script_text_editor/contextual_help", TTR("Contextual Help"), KeyModifierMask::ALT | Key::F1);
	ED_SHORTCUT_OVERRIDE("script_text_editor/contextual_help", "macos", KeyModifierMask::ALT | KeyModifierMask::SHIFT | Key::SPACE);
	ED_SHORTCUT("script_text_editor/toggle_bookmark", TTR("Toggle Bookmark"), KeyModifierMask::CMD_OR_CTRL | KeyModifierMask::ALT | Key::B);
	ED_SHORTCUT("script_text_editor/goto_next_bookmark", TTR("Go to Next Bookmark"), KeyModifierMask::CMD_OR_CTRL | Key::B);
	ED_SHORTCUT("script_text_editor/goto_previous_bookmark", TTR("Go to Previous Bookmark"), KeyModifierMask::CMD_OR_CTRL | KeyModifierMask::SHIFT | Key::B);
	ED_SHORTCUT("script_text_editor/remove_all_bookmarks", TTR("Remove All Bookmarks"), Key::NONE);
	ED_SHORTCUT("script_text_editor/goto_function", TTR("Go to Function..."), KeyModifierMask::ALT | KeyModifierMask::CTRL | Key::F);
	ED_SHORTCUT_OVERRIDE("script_text_editor/goto_function", "macos", KeyModifierMask::CTRL | KeyModifierMask::META | Key::J);
	ED_SHORTCUT("script_text_editor/goto_line", TTR("Go to Line..."), KeyModifierMask::CMD_OR_CTRL | Key::L);
	ED_SHORTCUT("script_text_editor/toggle_breakpoint", TTR("Toggle Breakpoint"), Key::F9);
	ED_SHORTCUT_OVERRIDE("script_text_editor/toggle_breakpoint", "macos", KeyModifierMask::META | KeyModifierMask::SHIFT | Key::B);
	ED_SHORTCUT("script_text_editor/remove_all_breakpoints", TTR("Remove All Breakpoints"), KeyModifierMask::CMD_OR_CTRL | KeyModifierMask::SHIFT | Key::F9);
	ED_SHORTCUT("script_text_editor/goto_next_breakpoint", TTR("Go to Next Breakpoint"), KeyModifierMask::CMD_OR_CTRL | Key::PERIOD);
	ED_SHORTCUT("script_text_editor/goto_previous_breakpoint", TTR("Go to Previous Breakpoint"), KeyModifierMask::CMD_OR_CTRL | Key::COMMA);
	ScriptEditor::register_create_script_editor_function(create_editor);
}
void ScriptTextEditor::validate() {
	this->code_editor->validate_script();
}