Add @UnsupportedAppUsage annotations

For packages:
  android.net
  android.net.wifi
  android.nfc

This is an automatically generated CL. See go/UnsupportedAppUsage
for more details.

Exempted-From-Owner-Approval: Mechanical changes to the codebase
which have been approved by Android API council and announced on
android-eng@

Bug: 110868826
Test: m
Change-Id: I7489aad1dceeb18ed7ca48a1ed8829a668b3fa04