fix(converter): handle null list lvlText and always clear numbering cache#2113

harbournick merged 1 commit intomainsuperdoc-dev/superdoc:mainfrom

nick/it-538-converter-gethtml-failing-in-headless-mode-w-null-lvltextsuperdoc-dev/superdoc:nick/it-538-converter-gethtml-failing-in-headless-mode-w-null-lvltextCopy head branch name to clipboard