Fix SetRequestedOrientationWhilePinnedTest with Shell transition

When the windowing mode is changed during fixed rotation, we don't want
to animate to the fixed rotation anymore, because the fixed rotation
will be cancelled later.

Bug: 214324061
Test: atest WMShellFlickerTests:SetRequestedOrientationWhilePinnedTest
Change-Id: I24b5389ec2b6ea28ce3ba7abf38fbd269566edf3