Revert @eslint/js to 9.x in /src/monarch to fix CI peer dependency conflict (#18973)

Reverts <a
href="https://github.com/eslint/eslint/tree/HEAD/packages/js">@eslint/js</a>
back to `^9.39.2` in `/src/monarch` and regenerates the lockfile.

`@eslint/js@10.0.1` requires `eslint@^10.0.0` as a peer dependency,
conflicting with the existing `eslint@9.x` installation and causing `npm
ci` to fail. Upgrading `eslint` to 10.x is not viable at this time
because `eslint-plugin-notice` uses the removed `context.getFilename()`
API.

Both `eslint` and `@eslint/js` are now pinned to `9.39.4`.

<br>

> **Note**
> Automatic rebases have been disabled on this pull request as it has
been open for over 30 days.

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Co-authored-by: brendandburns <5751682+brendandburns@users.noreply.github.com>

Author: 3 people