Remove unnecessary network policy rules bookkeeping

These data structures are maintained but never accessed for their
information. Removing these should not affect any behavior and
can free up a few KiBs of heap memory on devices with 100 or more apps
installed.

Flag: EXEMPT refactor

Test: atest FrameworksServicesTests:NetworkPolicyManagerServiceTest
Test: atest CtsHostsideNetworkPolicyTests

Bug: 327815574
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:f4f8319f335be057ab350e7e9e00126717629a4d)
Merged-In: I075af2696090387aefd1194e6e9d5a07a7d70299
Change-Id: I075af2696090387aefd1194e6e9d5a07a7d70299