Also a few utilities that were in the way, and some opportunistic
cleanups.
Test: FrameworksNetTest NetworkStackTest
Change-Id: I385070e2044fd967cb18f1ffea9a86a4627b742e
Use a MATCH_MOBILE_WILDCARD template to avoid filtering by
subscriberId when querying statistics from NetworkStatsService.
Bug: 74038898
Change-Id: I4b39e7031416cb33b23d89aa36ff0f774eaa942f
Fixes: 74038898
Test: runtest frameworks-net, CTS tests pass