Bump loader-utils and @mdx-js/loader in /web

Removes [loader-utils](https://github.com/webpack/loader-utils). It's no longer used after updating ancestor dependency [@mdx-js/loader](https://github.com/mdx-js/mdx/tree/HEAD/packages/loader). These dependencies need to be updated together.


Removes `loader-utils`

Updates `@mdx-js/loader` from 1.6.22 to 2.1.5
- [Release notes](https://github.com/mdx-js/mdx/releases)
- [Changelog](https://github.com/mdx-js/mdx/blob/main/changelog.md)
- [Commits](https://github.com/mdx-js/mdx/commits/2.1.5/packages/loader)

---
updated-dependencies:
- dependency-name: loader-utils
  dependency-type: indirect
- dependency-name: "@mdx-js/loader"
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]