PBAP: Sort vCardListing results when order is alphabetic

Usecase:
Send Get request from PBAP client for vCardListing with search
attribute as "number" and order is "alphabetic".

Issue:
vCardListing returned from Pbap Server doesn't follow alphabetic
order.

Root Cause:
Set of values fetched for the given number(Search Value) are ordered
by Contact_ID in the cursor query.

Fix:
Sort the entries alphabetically before writing vCardListing response
if order is set to alphabetic from Pbap client.

Test: After sending alphabetical search, verified that the received vcard
listing was in alphabetical order.

Bug: 37412583
Change-Id: Iff3d1f4aac998ef85b5cef862fd427cb8a57bdb4