USN-6374-2: Mutt vulnerabilities

USN-6374-1 fixed vulnerabilities in Mutt. This update provides the
corresponding updates for Ubuntu 23.10.

Original advisory details:

It was discovered that Mutt incorrectly handled certain email header
contents. If a user were tricked into opening a specially crafted message,
a remote attacker could possibly use this issue to cause a denial of
service. (CVE-2023-4874, CVE-2023-4875)