Finally fix the maddening long waiting times after clicking "Ok" in the import matcher window.

Turns out we were simply missing a suspend_gui_refresh call before actually
processing the results. Sigh.

(Can go into 2.4 because the bugfix is so surprisingly simple.)
BP

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@22929 57a11ea4-9604-0410-9ed3-97b8803252fd