### 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)
RS::get_singleton()->environment_set_ssr_roughness_quality(ssr_roughness_quality);
	RS::SubSurfaceScatteringQuality sss_quality = RS::SubSurfaceScatteringQuality(int(GLOBAL_GET("rendering/environment/subsurface_scattering/subsurface_scattering_quality")));
	RS::get_singleton()->sub_surface_scattering_set_quality(sss_quality);
	float sss_scale = GLOBAL_GET("rendering/environment/subsurface_scattering/subsurface_scattering_scale");
	float sss_depth_scale = GLOBAL_GET("rendering/environment/subsurface_scattering/subsurface_scattering_depth_scale");
	RS::get_singleton()->sub_surface_scattering_set_scale(sss_scale, sss_depth_scale);
	uint32_t directional_shadow_size = GLOBAL_GET("rendering/lights_and_shadows/directional_shadow/size");
	uint32_t directional_shadow_16_bits = GLOBAL_GET("rendering/lights_and_shadows/directional_shadow/16_bits");
	RS::get_singleton()->directional_shadow_atlas_set_size(directional_shadow_size, directional_shadow_16_bits);
	RS::ShadowQuality shadows_quality = RS::ShadowQuality(int(GLOBAL_GET("rendering/lights_and_shadows/positional_shadow/soft_shadow_filter_quality")));
	RS::get_singleton()->positional_soft_shadow_filter_set_quality(shadows_quality);
	RS::ShadowQuality directional_shadow_quality = RS::ShadowQuality(int(GLOBAL_GET("rendering/lights_and_shadows/directional_shadow/soft_shadow_filter_quality")));
	RS::get_singleton()->directional_soft_shadow_filter_set_quality(directional_shadow_quality);
	float probe_update_speed = GLOBAL_GET("rendering/lightmapping/probe_capture/update_speed");
	RS::get_singleton()->lightmap_set_probe_capture_update_speed(probe_update_speed);
	RS::EnvironmentSDFGIFramesToConverge frames_to_converge = RS::EnvironmentSDFGIFramesToConverge(int(GLOBAL_GET("rendering/global_illumination/sdfgi/frames_to_converge")));
	RS::get_singleton()->environment_set_sdfgi_frames_to_converge(frames_to_converge);
	RS::EnvironmentSDFGIRayCount ray_count = RS::EnvironmentSDFGIRayCount(int(GLOBAL_GET("rendering/global_illumination/sdfgi/probe_ray_count")));
	RS::get_singleton()->environment_set_sdfgi_ray_count(ray_count);
	RS::VoxelGIQuality voxel_gi_quality = RS::VoxelGIQuality(int(GLOBAL_GET("rendering/global_illumination/voxel_gi/quality")));
	RS::get_singleton()->voxel_gi_set_quality(voxel_gi_quality);
	RS::get_singleton()->environment_set_volumetric_fog_volume_size(GLOBAL_GET("rendering/environment/volumetric_fog/volume_size"), GLOBAL_GET("rendering/environment/volumetric_fog/volume_depth"));
	RS::get_singleton()->environment_set_volumetric_fog_filter_active(bool(GLOBAL_GET("rendering/environment/volumetric_fog/use_filter")));
	RS::get_singleton()->canvas_set_shadow_texture_size(GLOBAL_GET("rendering/2d/shadow_atlas/size"));
	bool use_half_res_gi = GLOBAL_GET("rendering/global_illumination/gi/use_half_resolution");
	RS::get_singleton()->gi_set_use_half_resolution(use_half_res_gi);
	bool snap_2d_transforms = GLOBAL_GET("rendering/2d/snap/snap_2d_transforms_to_pixel");
	scene_root->set_snap_2d_transforms_to_pixel(snap_2d_transforms);
	bool snap_2d_vertices = GLOBAL_GET("rendering/2d/snap/snap_2d_vertices_to_pixel");
	scene_root->set_snap_2d_vertices_to_pixel(snap_2d_vertices);