Add carrier privileges unit tests for ICCID access

SubscriptionController clears out the ICCID from the resulting
SubscriptionInfo object(s) if the caller does not meet the access
requirements for subscriber identifier access. This commit adds
unit tests to verify that callers with carrier privileges receive
the expected ICCID from the returned SubscriptionInfo object(s).

Bug: 152432892
Test: atest SubscriptionControllerTest
Change-Id: Ieb379ec663608a9fd277aa70fe8c654c1d51e195