This fixes a problem rendering multiple graphs on the same page
(https://github.com/mermaid-js/mermaid/pull/1190).

Full list of changes: https://github.com/mermaid-js/mermaid/releases

Mermaid v8.4.4 also fixes an HTML escaping issue
(https://github.com/mermaid-js/mermaid/issues/903). Since HTML labels
are disabled, the HTML content can remain as-is, and we just need to
ensure the XSS doesn't actually get run.

Closes https://gitlab.com/gitlab-org/gitlab/issues/195802