Remove removed package uids from Restricted Mode's uid allowlist

Currently uids from removed packages remain in Restricted Mode's uid allowlist.
This is unsafe given that new packages can be granted the uid and thereby network access by default.
This addresses the problem by listening for ACTION_PACKAGE_REMOVED and removing the uid from the allowlist.

Bug: https://issuetracker.google.com/issues/206947902
Change-Id: I16ee9a8aa869f6e4eaa9dfc494c588e74ac2e8f2
(cherry picked from commit c84c7adcedb16da65c5ce6b6f30441b64f1bcf85)