### 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)
result.output += errors[0].message + "\n"; 
		}
		if (!p_is_generating) {
			result.passed = check_output(result.output);
		}
		return result;
	}
#ifdef DEBUG_ENABLED
	StringBuilder warning_string;
	for (const GDScriptWarning &E : parser.get_warnings()) {
		const GDScriptWarning warning = E;
		warning_string.append(">> WARNING");
		warning_string.append("\n>> Line: ");
		warning_string.append(itos(warning.start_line));
		warning_string.append("\n>> ");
		warning_string.append(warning.get_name());
		warning_string.append("\n>> ");
		warning_string.append(warning.get_message());
		warning_string.append("\n");
	}
	result.output += warning_string.as_string();
#endif
	
	GDScriptCompiler compiler;
	err = compiler.compile(&parser, script.ptr(), false);
	if (err != OK) {
		enable_stdout();
		result.status = GDTEST_COMPILER_ERROR;
		result.output = get_text_for_status(result.status) + "\n";
		result.output = compiler.get_error();