Remove default Calls and SMS restrictions from the MAIN user.

Main user is a secondary user and in turns enherit the restriction of
DISALLOW_OUTGOING_CALLS and DISALLOW_SMS.
Refactored the user creation flow to ignore applying these
restrictions if the user being created is a MAIN user.

Bug: 294821532
Test: atest UserManagerTest#testMainUser_hasNoCallsOrSMSRestrictions -c
Change-Id: I7b2baa80c86400a1cb64dfcf12c4c93faa15b556