Revert "Fix NPE when reparenting a leash that has already been released."

This reverts commit 67f210f7.

Reason for revert: part of a revert chain to CP fix to b/404507270. The end state is the same as currently at ToT, but need to have cherry-pickable CLs for branches that are in CP mode.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:62c16670a9604468059235f950928a8e0ab7626b)
Merged-In: I6cc2bc9768b5603b5829c21a79456848376a7896
Change-Id: I6cc2bc9768b5603b5829c21a79456848376a7896