Merge "Completely remove pinned task when starting a new PiP" into tm-dev am: bfbf74ae

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18175783



Change-Id: I0e7480f11e5672011d87b6e7c51b1c0505153d02
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>