Ensure NetworkStats migrated snapshot is identical

Read migration snapshot both from the platform API and the legacy
method, and Log.wtf if they are different. Use the legacy method data if
they are.

This ensures that using the migration API is a no-op, and that errors
are reported (through Log.wtf) if it would not have been if used as-is.

Ignore-AOSP-First: in a topic with internal-only changes
Test: NetworkStatsServiceTest
Bug: 230289468
Change-Id: I857ad18183d63d1aa16e89f89eb24009648720a2
3 files changed