[MS54.3] Move NetworkStats to updatable sources

This CL builds NetworkStats related codes with the
connectivity module instead of platform.

Test: TH
Bug: 197717846
Change-Id: I4eeb7ea9cfc3139991caf0fc22474e0052a0391c
Merged-In: I4eeb7ea9cfc3139991caf0fc22474e0052a0391c
16 files changed