Use the new GTK2 `force` option rather than doing the force manually on the file

home/configurations/nmelzer_at_phoebe.nix

···
 
   services.playerctld.enable = true;
 
-  home.file."${config.gtk.gtk2.configLocation}".force = true;
+  gtk.gtk2.force = true;
 
   programs.ssh.includes = [
     config.sops.secrets.ssh.path