Fix missing Activity embedding allowlisting for Assistant.

The normal settings fragments are already allowlisted via SubSettingActivity.
ManageApplications fragment based activities are not compatible with that however.

The ManageApplications fragment has several modes that are selected by the activity name, hence cannot use the SpringboardSettings activity to launch just the fragment.

For more context, see
go/conversational-care-activity-embedding-allowlisting

BUG: 282921726

Change-Id: I65872b574ce6272fbd33ab7bd100504a6536f340