### 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)
case DEBUG_TOGGLE_BREAKPOINT: {
			Vector<int> caret_edit_order = tx->get_caret_index_edit_order();
			caret_edit_order.reverse();
			int last_line = -1;
			for (const int &c : caret_edit_order) {
				int from = tx->has_selection(c) ? tx->get_selection_from_line(c) : tx->get_caret_line(c);
				from += from == last_line ? 1 : 0;
				int to = tx->has_selection(c) ? tx->get_selection_to_line(c) : tx->get_caret_line(c);
				if (to < from) {
					continue;
				}
				
				bool selection_has_breakpoints = false;
				for (int line = from; line <= to; line++) {
					if (tx->is_line_breakpointed(line)) {
						selection_has_breakpoints = true;
						break;
					}
				}
				
				if (!selection_has_breakpoints) {
					if (tx->get_caret_line(c) != last_line) {
						tx->set_line_as_breakpoint(tx->get_caret_line(c), true);
					}
				} else {
					for (int line = from; line <= to; line++) {
						tx->set_line_as_breakpoint(line, false);
					}
				}
				last_line = to;