semantik: unmark broken on aarch64-linux

pkgs/applications/office/semantik/default.nix

···
   ];
 
   meta = with lib; {
-    broken = (stdenv.isLinux && stdenv.isAarch64);
     description = "A mind-mapping application for KDE";
     license = licenses.mit;
     homepage = "https://waf.io/semantik.html";