Remove RingtoneManager.*SyncFromParent APIs

These operations can be done already if the caller has
WRITE_SECURE_SETTINGS_PERMISSION, and the only approved callers are
settings apps which have that permission. We don't want anyone else
to bypass the permission check and turn off parent sounds sync.

Test: atest SettingsRoboTests
Bug: 204555055
Change-Id: I47956428f5363affef29af9dbe3d3dde21c5a392