search: remove additional params from activateResult() call

The only case when we're interested in using those parameters nowadays
is for DnD, which is handled in a separate method already.
Since we're not going to support DnD for non-app search results anyway,
drop the params from all the activateResults() calls; this will be
useful later since we're going to add another parameter to it.

https://bugzilla.gnome.org/show_bug.cgi?id=689735