I deleted certain topic from NodeBB with admin access now I am seeing this

#-Instant Verify (80 Point) on TOEFL IBT WITHOUT EXAM #(n*****@gmail.com)#
Study ____________ (topic)/topic_id

This topic has been deleted. Only users with topic management privileges can see it.

This topic's URL is present in the sitemap.xml file, which is affecting my site's SEO.
So I wanted a solution to update this indexing in the sitemap or how to update <meta name="robots" content="noindex, nofollow"> in the nodeBB for the deleted topics.