### 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 last_is_safe = false;
	for (int i = 0; i < te->get_line_count(); i++) {
		if (errors.is_empty()) {
			bool is_folded_code_region = te->is_line_code_region_start(i) && te->is_line_folded(i);
			te->set_line_background_color(i, is_folded_code_region ? folded_code_region_color : Color(0, 0, 0, 0));
		} else {
			for (const ScriptLanguage::ScriptError &E : errors) {
				bool error_line = i == E.line - 1;
				te->set_line_background_color(i, error_line ? marked_line_color : Color(0, 0, 0, 0));
				if (error_line) {
					break;
				}
			}
		}
		if (highlight_safe) {
			if (safe_lines.has(i + 1)) {
				te->set_line_gutter_item_color(i, line_number_gutter, safe_line_number_color);
				last_is_safe = true;
			} else if (last_is_safe && (te->is_in_comment(i) != -1 || te->get_line(i).strip_edges().is_empty())) {
				te->set_line_gutter_item_color(i, line_number_gutter, safe_line_number_color);
			} else {
				te->set_line_gutter_item_color(i, line_number_gutter, default_line_number_color);
				last_is_safe = false;
			}
		} else {
			te->set_line_gutter_item_color(i, 1, default_line_number_color);
		}
	}
}
void ScriptTextEditor::_update_bookmark_list() {