Highlight the currently selected deck when the deck list is updated.

There still remains cases where the deck list is updated and the StudyOptionsFragment is replaced (e.g., new filtered deck) but the currently selected deck isn't correctly highlighted in the deck list in fragmented mode. So the highlighted deck and the StudyOptionsFragment deck differ.

This change will ensure that any time the deck list is updated, the correct deck in the list is also highlighted. The assumption is made that the deck visible in the StudyOptionsFragment is internally set as the currently selected deck.