Remove PropertyInvalidatedCache.onTrimMemory

This method was only called for TRIM_MEMORY_COMPLETE, a signal that is
now deprecated and no longer issued. Remove the callsite and method for
now.

A follow-up effort may explore more targetted trimming and clearing for
caches that could have larger footprints than current ones.

Bug: 354774702
Test: m + presubmit
Flag: EXEMPT refactor
Change-Id: Iebe70537bfde5fe0480a38a3dbdc4a1e9296a6a8