Support video type for VirtualBackground

[devsideal]

Is your feature request related to a problem? Please describe. Can you provide support for video type in VirtualBackground.

Describe the solution you'd like If possible add one more type in VirtualBackgroundSource to give support for the video.

Describe alternatives you've considered Currently looks like, there is no way to show animated background in the video.

https://www.agora.io/en/blog/add-custom-backgrounds-to-your-live-video-calling-application-using-the-agora-android-uikit/