User current user context for CarrierServiceBindHelper

This CLs create current user context as the context for querying package
and bind/unbind carrier services.

In non-HSUM device, the behavior is not change for system user. For
HSUM, it will support carrier service binding for main user and other
secondary users if present.

Bug: 345523452
Test: atest FrameworkTelephonyTests
Test: Carrier service binding test on both Phone and Tablet
Flag: com.android.internal.telephony.flags.support_carrier_services_for_hsum
Change-Id: Ic8bf96555516c69ba6ad5c3a8d311dd05377d419