VideoModule: check for videosnapshot support in onSingleTapUp

onSingleTapUp is now triggered through PreviewGestures instead of
ActivityBase, so the check in initializeVideoSnapshot() is no
longer enough to prevent triggering video snapshot on unsupported
devices.

Change-Id: Iab0b4b3d0cd9b0ea7278eceee3ae58419f5df100