Update ImageBackground.js (#32055)
Update ImageBackground.js (#32055)

Summary:
Currently ImageBackGround component has optional style props, but if you don't pass it as prop, it still "thinks" you pass style and crushes.
In this pr, I made width and height inside component to be optional so it won't crush.

## Changelog

[General] [Fix] - Changed ImageBackground's style so it won't crush.

[Screen Shot 2021-08-20 at 15 05 45](https://user-images.githubusercontent.com/62840630/130230568-be02b1a2-52ec-4f9d-b3d3-212552d3882b.png)

As you can see in this component, I tried to use ImageBackground without any style props, and my app crushes. Then I added style with empty object and the app didn't crush anymore, as you can see here:
![Screen Shot 2021-08-20 at 15 09 23](https://user-images.githubusercontent.com/62840630/130230932-a576c397-a910-4e40-a202-56482d83dd9c.png).

In conclusion, if we make width and height styles optionals inside ImageBackground component, it won't crush anymore.

Thoughts:
Maybe consider to make style props for this component none-optional because it isn't make any sense that image won't have any style at all.

Thanks ahead, that was my first pr, Eden Binyamin.

Pull Request resolved: https://github.com/facebook/react-native/pull/32055

Reviewed By: charlesbdudley

Differential Revision: D30452297

Pulled By: sshic

fbshipit-source-id: b7071aa457dba443ed2f627c2458ea84fd24b36d

facebook/react-native,janicduplessis/react-native,janicduplessis/react-native,janicduplessis/react-native,javache/react-native,facebook/react-native,pandiaraj44/react-native,facebook/react-native,pandiaraj44/react-native,pandiaraj44/react-native,janicduplessis/react-native,facebook/react-native,pandiaraj44/react-native,janicduplessis/react-native,javache/react-native,javache/react-native,facebook/react-native,pandiaraj44/react-native,pandiaraj44/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,javache/react-native,pandiaraj44/react-native,javache/react-native,facebook/react-native,facebook/react-native,javache/react-native,janicduplessis/react-native,javache/react-native,pandiaraj44/react-native,javache/react-native,janicduplessis/react-native,facebook/react-native