A few missing pieces for logging in ExtServices

1. Log TYPE_ACTIONS_GENERATED with a list of suggestion type.
2. Log the score of the clicked suggestion.
    a) For replies, the score is stored in session.
    b) For actions, the score is stored in the extras.
3. Suppress logging if suggestions are not going to be used by SysUI
4. Removed @NonNull annotation. SmartActionsHelpers are fully annotated,
   so we only need @Nullable annotation.
5. TextClassificationManager cannot be null, and getTextClassifier()
   won't return null either, so removed some null checks.

Test: atest SmartActionsHelperTest
Test: Manual. Send a message to myself, observer generated event is
      loggeed. Tap on it, seeing the score is logged.
Test: Manual, send a message with app generated replies, observe that
      only generated event is logged.

BUG: 120803809

Change-Id: I1c18decb237cbeb267f2a3db6ebb149232b786b4