nfc(api): Address API council feedback for always on API

Comments addressed:
1. Since setControllerAlwaysOn takes an integer, should this be named
“setControllerAlwaysOnMode” instead?
2. How does the setControllerAlwaysOn in NfcOemExtension work?
Is it a replacement for the version in NfcAdapter? Should this be documented?
3. spelling : “operation has bee initiated” -> should be “operation has been initiated”

Bug: 368149547
Test: atest CtsNfcTestCases
Change-Id: If02c65a99797cc7221a58bef04da4756034d5d23