rosenthal: noctalia-shell: Add qtmultimedia input.

I didn't add the input because it didn't work.  That's true for now as well.
Adding it here in case it works one day.

* modules/rosenthal/packages/wm.scm (noctalia-shell) [inputs]: Add
qtmultimedia.

modules/rosenthal/packages/wm.scm

@@ -139,6 +139,7 @@ exec ~a --config ~a/etc/xdg/quickshell/noctalia-shell \"$@\"~%"
            noctalia-qs
            python-minimal
            qtbase
+           qtmultimedia
            qtwayland
            which
            wl-clipboard