Bump @guardian/identity-auth-frontend from 6.0.2 to 6.0.3

Bumps [@guardian/identity-auth-frontend](https://github.com/guardian/csnx) from 6.0.2 to 6.0.3.
- [Release notes](https://github.com/guardian/csnx/releases)
- [Commits](https://github.com/guardian/csnx/compare/@guardian/[email protected]...@guardian/[email protected])

---
updated-dependencies:
- dependency-name: "@guardian/identity-auth-frontend"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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