Check and remove all the secure keys in the site Mermaid Config, not just `securityLevel`. Unfortunately, the logic of Mermaid's `sanitize` function in `config.ts` is a bit convoluted. For instance, the `secure` config restricts keys deeply in the object. See: https://github.com/mermaid-js/mermaid/blob/9745f325cb9e1967640f0e85da193a2f820634f1/packages/mermaid/src/config.ts#L155-L190