Always cancel the ongoing recents transition when removing PIP

- Since launcher doesn't handle the closing of the PIP task, we
  should just end the ongoing transition

Fixes: 422660753
Flag: EXEMPT bugfix
Test: Enter overview with PIP, and then close the active PIP
Change-Id: Ia1bdb90cc3d4fa5b8139f7a3b0c72842703f6ce6