fix(deps): update dependency nodebb-theme-vanilla to v11.3.8 (#9031)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

install/package.json

@@ -105,7 +105,7 @@
         "nodebb-theme-lavender": "5.0.14",
         "nodebb-theme-persona": "10.2.98",
         "nodebb-theme-slick": "1.3.5",
-        "nodebb-theme-vanilla": "11.3.7",
+        "nodebb-theme-vanilla": "11.3.8",
         "nodebb-widget-essentials": "4.1.2",
         "nodemailer": "^6.4.6",
         "nprogress": "0.2.0",