### 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)
expression_pattern = COLOR_NAME;
				} else if (expression_pattern == COLOR_NAME && end < 0 && (line[i] == ' ' || line[i] == '\t')) {
					
					continue;
				} else if (expression_pattern == COLOR_NAME && !(line[i] == '_' || ('A' <= line[i] && line[i] <= 'Z'))) {
					end = i;
					break;
				}
			}
			switch (expression_pattern) {
				case RGBA_PARAMETER: {
					color_args = line.substr(begin, end - begin);
					String stripped = color_args.replace(" ", "").replace("\t", "").replace("(", "").replace(")", "");
					PackedFloat64Array color = stripped.split_floats(",");
					if (color.size() > 2) {
						float alpha = color.size() > 3 ? color[3] : 1.0f;
						color_picker->set_pick_color(Color(color[0], color[1], color[2], alpha));
					}
				} break;
				case COLOR_NAME: {
					if (end < 0) {
						end = line.length();
					}
					color_args = line.substr(begin, end - begin);
					const String color_name = color_args.replace(" ", "").replace("\t", "").replace(".", "");
					const int color_index = Color::find_named_color(color_name);
					if (0 <= color_index) {
						const Color color_constant = Color::get_named_color(color_index);
						color_picker->set_pick_color(color_constant);
					} else {