hap: Align callback names to match API calls

This change was requested in b/218616250

Bug: 150670922
Bug: 218616250
Tag: #feature
Test: atest CtsBluetoothTestCases:android.bluetooth.cts.BluetoothHapClientTest
Sponsor: jpawlowski@
Change-Id: I4ef0b8b5d345e717a6c6cfc9bb3663bb11c170ac