Exit split selection state if launcher interrupted

* Launcher gets paused as a natural part of
confirming a split, so only cancel when 1 app is
confirmed

Test: Start split from workspace, then go to
* double tap camera
* settings via notification drawer
* mic icon on QSB
Bug: 276361926

Change-Id: I048964403303defe35035ee24950cfbbfc201afd
3 files changed