Re-calculate mLastComputedCarouselTaskSize when its empty before getMaxScaleForFullScreen

- Follow-up on ag/26499257 to do the same on mLastComputedCarouselTaskSize
- Also changing the mLastComputedTaskSize check to isEmpty

Bug: 326550571
Flag: none
Test: Swipe up, quick switch with Pixel / 3P launcher
Change-Id: If934bf4baf2782cd752b5621ad5e9be4a2013c49
1 file changed