Add unit test for Remote SIM functionality

Currently there are no unit tests to verify the behavior of the Remote SIM with no FEATURE_TELEPHONY_SUBSCRIPTION and the config_force_phone_globals_creation in place.

These tests would be essential for making sure that 1) the config that was put in place stays in place for the time being and that 2) when mocking these values, the APIs function correctly even with no FEATURE_TELEPHONY_SUBSCRIPTION support.

Additionally, this change reconfigures other functions used for Remote SIM functionality (addSubInfo, removeSubInfo, and getActiveSubscriptionInfoForIccId) within packages/modules/Bluetooth/android/app/src/com/android/bluetooth/mapclient/MapClientContent.java.

See go/remote-sim-testing for additional context.

Flag: TEST_ONLY
Bug: 394918135
Test: atest SubscriptionManagerServiceTest
Change-Id: I22e349f9c62e3af5b70bcf6cb2b27613b8e4e260