chore(nix): move forticlient-vpn to host file

darwin/homebrew-common.nix

@@ -58,7 +58,6 @@
     "font-monaspace"
     "font-noto-emoji"
     "font-symbols-only-nerd-font"
-    "forticlient-vpn" # Free VPN client for FortiClient
     "google-japanese-ime" # Japanese input software
     "gpg-suite-no-mail" # Tools to protect your files
     "hammerspoon" # Desktop automation application

hosts/mac-mini/homebrew.nix

@@ -5,6 +5,7 @@
   casks = [
     "ankerwork" # Webcam & audio device software
     "daisydisk" # Disk space visualiser
+    "forticlient-vpn" # Free VPN client for FortiClient
     "gemini" # Disk space cleaner that finds and deletes duplicated and similar files
     "handbrake" # Open-source video transcoder. FIX: Broken on nixpks
     "lbry" # Official client for LBRY, a decentralised file-sharing and payment network