Revert "Make leash cleanup on-demand instead of default."

This reverts commit aa02d1b4.

Reason for revert: partial revert 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.

Change-Id: I0a71ffba496db856ba29ebe9ab9b453aad927bc4