DropdownInputWidget: Give un-infused widget cursor:pointer
DropdownInputWidget: Give un-infused widget cursor:pointer

Matches the style of a JS DropdownInputWidget.

Change-Id: I2c0299882fcfa6845e523be6f9b0faf846ca4e13

wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui,wikimedia/oojs-ui