fix(panel/i18n): add missing users_col_user key to translation files

panel/src/i18n/resources/en-US/admin.json

@@ -124,6 +124,7 @@
    "users_role_admin": "Admin",
      "users_role_owner": "Owner",
      "users_role_user": "User",
+  "users_col_user": "User",
   "users_col_role": "Role",
   "users_col_servers": "Servers",
   "users_col_status": "Status",

panel/src/i18n/resources/zh-CN/admin.json

@@ -124,6 +124,7 @@
   "users_role_admin": "管理员",
     "users_role_owner": "所有者",
     "users_role_user": "普通用户",
+  "users_col_user": "用户",
   "users_col_role": "角色",
   "users_col_servers": "服务器数",
   "users_col_status": "状态",