Continue the pausing process after automatically entering pip

Or the activity remained in PAUSING state and prevents the
activity to stop after screen off until stop timeout.

Bug: 202345179
Test: atest PinnedStackTests
Change-Id: Ibb8b3c48d483dcb96207ec2395a87b31d8eb107e
Merged-In: Ibb8b3c48d483dcb96207ec2395a87b31d8eb107e
(cherry picked from commit e84bd0d141b31d9504edf2d73591b2b8266f02e3)
2 files changed