fix(nginx): skip post-create config when nginx is stopped

When nginx is stopped (e.g. during traefik/caddy tests), the
post-create trigger should not attempt to build and reload the
nginx config as the service is not running.

plugins/nginx-vhosts/post-create

@@ -15,6 +15,10 @@ trigger-nginx-vhosts-post-create() {
     return
   fi
 
+  if [[ "$(fn-plugin-property-get "nginx" "--global" "proxy-status")" == "stopped" ]]; then
+    return
+  fi
+
   nginx_build_config "$APP"
 }