Update mermaid to
[v11](https://github.com/mermaid-js/mermaid/releases/tag/v11.0.0) and
enable the new [`suppressErrorRendering`
option](https://github.com/mermaid-js/mermaid/pull/4359) to ensure
mermaid never renders error elements into the DOM (we have per-chart
error rendering, so don't need it). Tested various chart types.
BTW, I was unable to reproduce that error rendering from mermaid with
`suppressErrorRendering: false` and I thought we had some CSS to hide
the error element, but I could not find it, not even in git history.
None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
61105d0618
because of a deprecation that was not showing before the rename).
`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.
Everything appears to work fine.
