Fix cite/template dialogs

I1a7fc7f2 broke cite/template dialog - onDescriptionClick is not defined.
I can't find it anywhere in the VE-MW or OOUI source.
Before my change, it was simply a no-op. But now we try to bind it in a way
that breaks everything. This commit just removes that line since it was
apparently not doing anything.

Bug: 67814
Change-Id: I0b9c3318b3de8530e0ba9e355cd73eb7f70a6b5a