[Wifi] Clear calling identity before permissions check

WifiManager API getConnectionInfo() must clear calling identity before
calling internal APIs that check permissions. This CL saves the calling
identity before clearing it and passed it on to the permission checks
method and restores it after.

Bug: 69725889
Test: On device tests, to repro the issue, Unit tests, QR Provisioning
tests
Change-Id: I7c182e934bf1e8a6ca41fd11dd67add36aef7992
5 files changed