### 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)

}
		List<StringName> animations;
		sf->get_animation_list(&animations);
		int frame = get_animation()->track_get_key_value(get_track(), p_index);
		String animation_name;
		if (animations.size() == 1) {
			animation_name = animations.front()->get();
		} else {
			
			String animation_path = get_animation()->track_get_path(get_track());
			animation_path = animation_path.replace(":frame", ":animation");
			int animation_track = get_animation()->find_track(animation_path, get_animation()->track_get_type(get_track()));
			float track_time = get_animation()->track_get_key_time(get_track(), p_index);
			int animaiton_index = get_animation()->track_find_key(animation_track, track_time);
			animation_name = get_animation()->track_get_key_value(animation_track, animaiton_index);
		}
		Ref<Texture2D> texture = sf->get_frame_texture(animation_name, frame);
		if (!texture.is_valid()) {
			return AnimationTrackEdit::get_key_rect(p_index, p_pixels_sec);
		}
		size = texture->get_size();
	}
	size = size.floor();
	Ref<Font> font = get_theme_font(SNAME("font"), SNAME("Label"));
	int font_size = get_theme_font_size(SNAME("font_size"), SNAME("Label"));
	int height = int(font->get_height(font_size) * 2);
	int width = height * size.width / size.height;
	return Rect2(0, 0, width, get_size().height);
}
bool AnimationTrackEditSpriteFrame::is_key_selectable_by_distance() const {