Bug when exporting with background image
**Describe the bug**
If you export the background image the background picture will not scale correctly.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to https://vinoth.info/react-sketch-canvas/
2. Use any image url for the background image (for example: https://upload.wikimedia.org/wikipedia/en/d/d4/Mickey_Mouse.png)
3. click export image
4. Background image is not exported with correct scale shown on canvas
![image](https://user-images.githubusercontent.com/98369477/201003612-1032285b-ffdd-4e0f-a0ee-d9df357a2abc.png)

5. Set xMinYMin for preserveBackgroundImageAspectRatio
6. click export image
7. Background image is broken
![image](https://user-images.githubusercontent.com/98369477/201003955-40b98d34-be04-49d2-9e1d-213f119ce4fe.png)



**Expected behavior**
Image should export like so when not using preserve background image ratio
![image](https://user-images.githubusercontent.com/98369477/201003501-c5124736-68db-4e70-97df-d15dd00b5db8.png)

Image should export like so when using xMinYmin
![image](https://user-images.githubusercontent.com/98369477/201004017-3e4350b0-6626-418e-af6b-6b4ad8acf8a2.png)




**Desktop (please complete the following information):**
 - Windows
 - Chrome