fish: Do not set enable wayland for firefox here

We will enable this via systemd environment.d support.

fish/.config/fish/config.fish

@@ -5,7 +5,6 @@ set -gx NIX_PATH {$HOME}/.nix-defexpr/channels
 export BROWSER='firefox'
 export MANPAGER='nvim +Man!'
 export NIX_SSL_CERT_FILE='/etc/ssl/certs/ca-certificates.crt'
-export MOZ_ENABLE_WAYLAND=1
 
 if [ -n "$NVIM_LISTEN_ADDRESS" ]
   export VISUAL="floaterm"