### 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)
bool has_active_tab = false;
	if (p_config_file->has_section_key(EDITOR_NODE_CONFIG_SECTION, "selected_bottom_panel_item")) {
		int selected_bottom_panel_item_idx = p_config_file->get_value(EDITOR_NODE_CONFIG_SECTION, "selected_bottom_panel_item");
		if (selected_bottom_panel_item_idx >= 0 && selected_bottom_panel_item_idx < bottom_panel_items.size()) {
			
			if (bottom_panel_items[selected_bottom_panel_item_idx].button->is_visible()) {
				_bottom_panel_switch(true, selected_bottom_panel_item_idx);
				has_active_tab = true;
			}
		}
	}
	if (p_config_file->has_section_key(EDITOR_NODE_CONFIG_SECTION, "center_split_offset")) {
		int center_split_offset = p_config_file->get_value(EDITOR_NODE_CONFIG_SECTION, "center_split_offset");
		center_split->set_split_offset(center_split_offset);
		
		if (!has_active_tab) {
			bottom_panel_items[0].control->show(); 
			_bottom_panel_switch(false, 0);
		}
	}
	
	if (p_config_file->has_section_key(EDITOR_NODE_CONFIG_SECTION, "selected_default_debugger_tab_idx")) {
		int selected_default_debugger_tab_idx = p_config_file->get_value(EDITOR_NODE_CONFIG_SECTION, "selected_default_debugger_tab_idx");
		EditorDebuggerNode::get_singleton()->get_default_debugger()->switch_to_debugger(selected_default_debugger_tab_idx);
	}
	
	if (p_config_file->has_section_key(EDITOR_NODE_CONFIG_SECTION, "selected_main_editor_idx")) {