Remove eval() from field_ui.js

In core/modules/field_ui/field_ui.js we currently have this:

 120         // Create the row handler, make it accessible from the DOM row element.
 121         var rowHandler = eval('new rowHandlers.' + data.rowHandler + '(row, data);');
 122         $(row).data('fieldUIRowHandler', rowHandler);

I see no reason for using eval() here. Simple bracket notation is enough and looks cleaner.

 120         // Create the row handler, make it accessible from the DOM row element.
 121         var rowHandler = new rowHandlers[data.rowHandler](row, data);
 122         $(row).data('fieldUIRowHandler', rowHandler);