[Passpoint] Add API to indicate OSU profile and expiration

Add an API to indicate if a profile was provisioned by an OSU
(subscription) server. This is necessary for the settings app
to handle profile expiration date use cases, which are different
between R1 (non-OSU) cases and R2 cases.
Make the getSubscriptionExpirationTimeInMillis API public.

Bug: 141474717
Test: atest PasspointConfigurationTest
Test: atest ConfigParserTest
Test: Complete OSU registration, verify API returns true
Test: Install R1 profile, verify API returns false
Change-Id: I788108f973a47716c5d7c9353eafedd5fb06cb8e