Update eslint and all plugins. Many plugins still do not ship type
definitions so I had to add stubs. Also, I had to put a few typescript
error expectations because if some unknown error in the types.
`eslint-plugin-no-jquery` is disabled because it's not compatible with
eslint 9 flat config
(https://github.com/wikimedia/eslint-plugin-no-jquery/issues/311).
1. Enable
[`@typescript-eslint/no-unnecessary-type-conversion`](https://typescript-eslint.io/rules/no-unnecessary-type-conversion/),
I think the two cases that were hit are safe cases.
2. Disable `no-new-func`, `@typescript-eslint/no-implied-eval` does the
same but better.
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.
