### Godot version

4.0beta17

### System information

Linux Mint 21.1

### Issue description

When editing animations for the **frame** property of **Sprite2D**, the preview image does not respect the **region_rect** specified in the Sprite2D's properties.

Godot 4.0 (tested with alpha1 to beta17)
![Screenshot from 2023-02-05 21-19-29](https://user-images.githubusercontent.com/2348534/216868394-45a9dc42-ce4b-4b11-82cb-4491aea46d9b.png)

Godot 3.5
![Screenshot from 2023-02-05 21-19-43](https://user-images.githubusercontent.com/2348534/216868543-cff6eb60-a431-4138-8fa6-5c30a54de0e1.png)

As can be seen in the second screenshot, the region rect is applied to the key preview image in Godot 3.5, but is ignored in Godot 4.0.


### Steps to reproduce

Steps:

1. Set a region rect on a Sprite2D node
2. Add Sprite2D.frame as a track to an AnimationPlayer
3. Insert key
4. Key preview does not take region rect into account

### Minimal reproduction project

[MRP.zip](https://github.com/godotengine/godot/files/10637055/MRP.zip)

Object *object = ObjectDB::get_instance(id);
	if (!object) {
		return AnimationTrackEdit::get_key_rect(p_index, p_pixels_sec);
	}
	Size2 size;
	if (Object::cast_to<Sprite2D>(object) || Object::cast_to<Sprite3D>(object)) {
		Ref<Texture2D> texture = object->call("get_texture");
		if (!texture.is_valid()) {
			return AnimationTrackEdit::get_key_rect(p_index, p_pixels_sec);
		}
		size = texture->get_size();
		if (bool(object->call("is_region"))) {
			size = Rect2(object->call("get_region_rect")).size;
		}
		int hframes = object->call("get_hframes");
		int vframes = object->call("get_vframes");
		if (hframes > 1) {
			size.x /= hframes;
		}
		if (vframes > 1) {
			size.y /= vframes;
		}
	} else if (Object::cast_to<AnimatedSprite2D>(object) || Object::cast_to<AnimatedSprite3D>(object)) {
		Ref<SpriteFrames> sf = object->call("get_sprite_frames");
		if (sf.is_null()) {
			return AnimationTrackEdit::get_key_rect(p_index, p_pixels_sec);