Bump sprockets-rails from 3.2.2 to 3.4.0 (#16990)

Bumps [sprockets-rails](https://github.com/rails/sprockets-rails) from 3.2.2 to 3.4.0.
- [Release notes](https://github.com/rails/sprockets-rails/releases)
- [Commits](https://github.com/rails/sprockets-rails/compare/v3.2.2...v3.4.0

)

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

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

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