TS 28.623 Rel17 CR Remove notifyFileDeletion as notification type
requested to merge TS_28.623_Rel17_CR_Remove_notifyFileDeletion_as_notification_type into Integration_Rel17_SA5_155_YANG
Remove "notifyFileDeletion" as notification type in _3gpp-commmon-files, since this notification type does not exist.