TeleService: fix event settings NPE

Has a bug in this commit when open Subscription settings:
Event settings already in Subscription settings - GSM call settings

http://review.cyanogenmod.org/#/c/74451/

PS2: This setting is added for non-world GSM phones only.
     Move this logic into the block that only gets executed for this case.
PS3: * Fix Event Notificatons for World Phone use case.
     * Don't call remove optional twice for msim.

Change-Id: I33fa9238b5a1715ce8a045a6d0b80bc66f9387e2