### 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)

int end = ofs + len * get_timeline()->get_zoom_scale();
			if (end >= get_timeline()->get_name_limit() && end <= get_size().width - get_timeline()->get_buttons_width() && ABS(mm->get_position().x - end) < 5 * EDSCALE) {
				len_resizing_start = false;
				use_hsize_cursor = true;
				len_resizing_index = i;
			}
			if (ofs >= get_timeline()->get_name_limit() && ofs <= get_size().width - get_timeline()->get_buttons_width() && ABS(mm->get_position().x - ofs) < 5 * EDSCALE) {
				len_resizing_start = true;
				use_hsize_cursor = true;
				len_resizing_index = i;
			}
		}
		over_drag_position = use_hsize_cursor;
	}
	if (len_resizing && mm.is_valid()) {
		
		len_resizing_rel += mm->get_relative().x;
		float ofs_local = len_resizing_rel / get_timeline()->get_zoom_scale();
		float prev_ofs_start = get_animation()->audio_track_get_key_start_offset(get_track(), len_resizing_index);
		float prev_ofs_end = get_animation()->audio_track_get_key_end_offset(get_track(), len_resizing_index);
		Ref<AudioStream> stream = get_animation()->audio_track_get_key_stream(get_track(), len_resizing_index);
		float len = stream->get_length();
		if (len == 0) {
			Ref<AudioStreamPreview> preview = AudioStreamPreviewGenerator::get_singleton()->generate_preview(stream);
			float preview_len = preview->get_length();
			len = preview_len;
		}
		if (len_resizing_start) {
			len_resizing_rel = CLAMP(ofs_local, -prev_ofs_start, len - prev_ofs_end - prev_ofs_start) * get_timeline()->get_zoom_scale();
		} else {