lp1792995 wrong row details shown on billing grid

lp1792995 wrong row details shown on billing grid

When using the bill grid, if one right clicks on a row and views full
details one is taken to the first selected row.  Make the UI show
full details for the row being right clicked on.  If no row is
clicked on show first selected item's details.

Signed-off-by: Mike Risher <mrisher@catalyte.io>
 Changes to be committed:
	modified:   Open-ILS/web/js/ui/default/staff/circ/patron/bills.js
	modified:   Open-ILS/web/js/ui/default/staff/services/grid.js

Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: Chris Sharp <csharp@georgialibraries.org>