Hold wifi and mobile interfaces since boot in NetworkStatsService am: a2f1cf3576 am: 40dfeb8ee2

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/18710006

Change-Id: I221c83423253034dfbb10df4333fb964d6ef7ee5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>