Fix broken azure-static-website workflow on PRs from forks

[hanrodz]

Pending investigation.

Some ideas:

• Does the azure-static-website workflow allow staging environment deployments for PRs from forks? How?
• In the case that it's not possible or too costly:
  • Set up staging environment in the form of a dev branch that doesn't trigger the workflow on PR, only on merge.
  • Once validated another PR would be required from dev into main.