fix(videoBackground): preserve aspect ratio on mobile devices

Using an android phone you should now be able to turn on and off video background effects without distorting the image for the other participants. Note: it will NOT look the same as before (see screenshot) but that's ok, the aspect ratio is preserved and as an added bonus, the grid view is consistent now.

Also we noticed a bug during development that prevented you from turning on or off background effects while the local video (top left video that shows your self) was NOT rendered. So please also test the following scenarios

On an android phone,

• turn on the video effects while in a meeting
• check if they actually turn on
• turn off the video effects
• check if they actually turn off

On a desktop, make the browser view so small that you cannot see yourself any more and repeat the steps above

On an iphone the background effect option should be disabled, i added an iPhone to the screenshot (bottom left grid item) just to demonstrate that the image looks the same as the android image and there are no distortions.

Closes #2212