Use apn id which contains default type when merging apns

In case of the following conditions, UI does not show preferred apn.
1. there are default and mms profile, respectively.
2. apns for default and mms are same.
3. mms profile is prior to default profile.

To fix it, use apn id which contains default type when merging apns.

Bug: 22641500
Change-Id: Ieec521f715f137aa7a827ee010390e3c47b35da1