create-normal-user: restore compatibility with Bookworm/Jammy
--logmsglevel was added in adduser 3.135, which is available in Trixie and Noble, so compatibility with Bookworm, Jammy and other older releases is broken:
Check the version before using it. Unfortunately it was not added to --help so we can't check for the actual option, and we have to check for the package version instead.
Follow-up for 9c033b3d