Update null cipher notification mutator API naming to match accessor

This commit updates the mutator API name to
setNullCipherNotificationsEnabled to maintain consistency with the
accessor API isNullCipherNotificationsEnabled.

Bug: 321949243
Test: atest TelephonyManagerTest
Change-Id: Id267e6cce87d6533b3128a94c0747f9c2b0667a6
3 files changed