build(deps): bump @lexical/utils from 0.19.0 to 0.21.0

Bumps [@lexical/utils](https://github.com/facebook/lexical/tree/HEAD/packages/lexical-utils) from 0.19.0 to 0.21.0.
- [Release notes](https://github.com/facebook/lexical/releases)
- [Changelog](https://github.com/facebook/lexical/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/lexical/commits/v0.21.0/packages/lexical-utils)

---
updated-dependencies:
- dependency-name: "@lexical/utils"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>