Check for GitHub Action caches before continuing

[colinrotherham]

Description

We're having problems with GitHub Actions cache/restore not working today, immediately after saving

This PR adds fail-on-cache-miss: true to make sure we correctly stop the build when this happens

The GitHub status board is all green but others are reporting it:

• https://github.com/actions/cache/issues/1621
• https://github.com/orgs/community/discussions/163260

Checklist

• [ ] Tested against our testing policy (Resolution, Browser & Accessibility)
• [ ] Follows our coding standards and style guide
• [ ] CHANGELOG entry