### 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)
OS::get_singleton()->set_stdout_enabled(true);
	OS::get_singleton()->set_stderr_enabled(true);
}
void GDScriptTest::disable_stdout() {
	
	OS::get_singleton()->set_stdout_enabled(false);
	OS::get_singleton()->set_stderr_enabled(false);
}
void GDScriptTest::print_handler(void *p_this, const String &p_message, bool p_error, bool p_rich) {
	TestResult *result = (TestResult *)p_this;
	result->output += p_message + "\n";
}
void GDScriptTest::error_handler(void *p_this, const char *p_function, const char *p_file, int p_line, const char *p_error, const char *p_explanation, bool p_editor_notify, ErrorHandlerType p_type) {
	ErrorHandlerData *data = (ErrorHandlerData *)p_this;
	GDScriptTest *self = data->self;
	TestResult *result = data->result;
	result->status = GDTEST_RUNTIME_ERROR;
	StringBuilder builder;
	builder.append(">> ");
	
	
	bool include_source_info = false;
	switch (p_type) {
		case ERR_HANDLER_ERROR:
			builder.append("ERROR");
			break;
		case ERR_HANDLER_WARNING:
			builder.append("WARNING");