[MS49] Remove NetworkStats hidden Api usages

This includes:
1. Remove unused INetworkStatsService and NetworkStatsHistory.
2. Replace NetworkTemplate usages with builder.
3. Replace TrafficStats references to DataUnit.
4. Reimplement NetworkTemplate#normalize.

Test: make RunSettingsRoboTests
Bug: 204830222
Change-Id: I8efecda5df403e9ed588daecd169cb3498d213a2