Update SubscriptionManager API by replacing 'id' & 'idx' with 'index'.

Bug: 35767068
Test: No build failure on update.
Change-Id: Ib7211a9d0c10a717bfd5a7b22b8bea2b3973d12f
Merged-in: Ib7211a9d0c10a717bfd5a7b22b8bea2b3973d12f
1 file changed