Validate aspect ratio on PiP params change.

If the params do not provide the aspect ratio we will return 0f, which
impacts further computations on e.g. pinch resize gesture.

Bug: 276455406
Test: manually modify ApiDemos to not provide aspect ratio, enter PiP
and verify that aspect ratio is set to default value instead of 0

Change-Id: Ie734a4e35ccbccdad5a2bee0f0e1bd507dcc1025