Add test that quick switch on pair-to-pair should never enter pip.

Verify pair-to-pair switch should not trigger auto-pip, and the
pip-able activity should not re-show during transition.

Bug: 290857445
Test: atest SwitchBetweenSplitPairsNoPip
Change-Id: I496c863fbeaa0ae4d4b8de512aecaaaf5d27dc5d