Offset src-rect by display cutouts if needed

For PiP2, we need to make sure source rect hint is adjusted
by display cutouts if needed to avoid flickers when entering.

Also refactored code portions handling fixed rotation in PiP2.

Bug: 377957432
Flag: com.android.wm.shell.enable_pip2
Test: enter fixed rotation PiP2 from ROTATION_90 on felix apidemos

Change-Id: I813245950213db4289e3b076bd7301be2be8847c