The user doesn't understand current behavior when hitting enter in find bar it opens first item of result list.

Change behavior to the following:

• Blank search term: no highlight (same as today and no opening of top result when hitting enter on blank search)
• User types a search term: highlight top result (see mock up)
• Hit enter: open highlighted result
• Arrows Up & Down (also see MGNLUI-4693):
  • change selected line (same as today)
  • cursor remains on findbar, user can continue search (same as today)
  • when going up with the arrows, once the top result is reached, do nothing, i.e. keep top result highlighted even if the arrow up is pressed further
• When the focus is not on top and the user changes or enhances the search term, the focus highlights the top result again