Don't override PiP windowing mode in LPM

This change fixes a regression caused by ag/26034822, where PiP
gets unexpectedly expanded via intent.

Note that this CL is simpler than the original CL merged to
main-arc-dev, as I've just realized excluding PIP win mode is
sufficient to fix the regression.

Bug: 323209868
Test: PinnedStackTests#testLaunchTaskByAffinityMatchSingleTask
Change-Id: I82eafd441c7667a7275ef85dd5ed3ee94cb3e9ff
(cherry picked from commit eef52ebe84c8f581602bad047b7df030ddc9fac2)