Inline readNetworkStatsDetailInternal, make mUseBpfStats final

This change inlines the logic from readNetworkStatsDetailInternal, and
reduces reundant checks in mUseBpfStats

Bug: 113122541
Test: atest FrameworksNetTests run, passing
Change-Id: If2ef8d8f038f32c8cf974aa02cfc1dc7e44dbad3
1 file changed
tree: 1f6ecd4cd5966bd3ffdadb87d78771b4c273b650
  1. core/
  2. services/
  3. wifi/