Is there any reason why you shouldn’t “clean-up” your XML sitemap and remove any URL that redirects to another page?
The only reason why you wouldn’t follow best practices suggested by Google for your XML sitemap and remove a 301 redirect would be if you were intentionally creating a sitemap that was full of your 301 redirected pages. You can use this intentionally created list of redirects during a migration or to resolve an issue of indexation where your new page urls are not getting indexed properly.
By creating a specific list of pages that have those 301 redirect codes, you can keep track of Google’s progress of identifying the new url. Of course, best practice here is of course to REMOVE that sitemap once you’ve seen Google properly crawl and recognize the new URLs. So at the end of the process, no, you do not want to KEEP 301 redirects in your Sitemap file.