WifiMetrics: Add link probe event to StaEvent

Add link probe event type to StaEvent in order to correlate link probe
success/failure with other StaEvents (e.g. disconnection, score breach).

Bug: 112029045
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh
Change-Id: Ice7a4f3f775cf399c74586e913d9db6dc5c806e3
3 files changed