Throw RuntimeException when looper is not prepared for deprecated API

Modified to send RuntimeException if Looper is not prepared when
using deprecated addOnSubscriptionsChangedListener.

With the feature of the "Lazily init Handler in SubscriptionManager",
we expected to avoid using addOnSubscriptionsChangedListener, which
has been deprecated. However, if the Looper is not prepared while
using addOnSubscriptionsChangedListener, which was deprecated,
previously a RuntimeException would have been thrown, but currently
a NullpointerException will be caused. For backward compatibility,
Modified it to generate a RuntimeException.

Bug: 314924913
Test: manual test
Test: atest SubscriptionManagerTest
Change-Id: I32a117eaac557a901bd78584013c9d5e4b0c5b4d