Revert "Pass main executor to ActivityLaunchAnimator"

Revert "Pass main executor to ActivityLaunchAnimator"

Revert submission 11213348-launch-animation-leak

Reason for revert: Regression b/156840927
Reverted Changes:
Id43847e3d:Break strong ref to ExpandableNotificationRow
I57ffe83b7:Pass main executor to ActivityLaunchAnimator
I5bddc38ac:Pass main executor to ActivityLaunchAnimator
Fixes: b/156840927

Change-Id: I6c6bc9c9497cb2517eb1900c55d2b6e409d3e7eb