### 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)
static int audio_driver_idx = -1;
static bool single_window = false;
static bool editor = false;
static bool project_manager = false;
static bool cmdline_tool = false;
static String locale;
static bool show_help = false;
static uint64_t quit_after = 0;
static OS::ProcessID editor_pid = 0;
#ifdef TOOLS_ENABLED
static bool found_project = false;
static bool auto_build_solutions = false;
static String debug_server_uri;
#ifndef DISABLE_DEPRECATED
static int converter_max_kb_file = 4 * 1024; 
static int converter_max_line_length = 100000;
#endif 
HashMap<Main::CLIScope, Vector<String>> forwardable_cli_arguments;
#endif
static bool single_threaded_scene = false;
static DisplayServer::WindowMode window_mode = DisplayServer::WINDOW_MODE_WINDOWED;
static DisplayServer::ScreenOrientation window_orientation = DisplayServer::SCREEN_LANDSCAPE;
static DisplayServer::VSyncMode window_vsync_mode = DisplayServer::VSYNC_ENABLED;
static uint32_t window_flags = 0;
static Size2i window_size = Size2i(1152, 648);
static int init_screen = DisplayServer::SCREEN_PRIMARY;
static bool init_fullscreen = false;
static bool init_maximized = false;
static bool init_windowed = false;
static bool init_always_on_top = false;