Bump katex from 0.15.6 to 0.16.0 (#616)

Bump katex from 0.15.6 to 0.16.0 (#616)

* Bump katex from 0.15.6 to 0.16.0

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.15.6 to 0.16.0.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](https://github.com/KaTeX/KaTeX/compare/v0.15.6...v0.16.0)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
* Remove copy-tex.css as it no longer required

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Krishan <33421343+kfiven@users.noreply.github.com>