### 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)

#include "animation_track_editor_plugins.h"
#include "editor/audio_stream_preview.h"
#include "editor/editor_resource_preview.h"
#include "editor/editor_scale.h"
#include "editor/editor_undo_redo_manager.h"
#include "scene/2d/animated_sprite_2d.h"
#include "scene/2d/sprite_2d.h"
#include "scene/3d/sprite_3d.h"
#include "scene/animation/animation_player.h"
#include "scene/resources/text_line.h"
#include "servers/audio/audio_stream.h"
int AnimationTrackEditBool::get_key_height() const {
	Ref<Texture2D> checked = get_theme_icon(SNAME("checked"), SNAME("CheckBox"));
	return checked->get_height();
}
Rect2 AnimationTrackEditBool::get_key_rect(int p_index, float p_pixels_sec) {
	Ref<Texture2D> checked = get_theme_icon(SNAME("checked"), SNAME("CheckBox"));
	return Rect2(-checked->get_width() / 2, 0, checked->get_width(), get_size().height);
}
bool AnimationTrackEditBool::is_key_selectable_by_distance() const {