ci: [DX-3555] Add Azure cleanup workflow

[witwash]

Summary

We've uploaded everything into the root blob folder (the root of mews-ui-widgetbook), but it had to be in the release folder, so the Web app can work correctly.
Doing anything without credentials requires a bunch of requests etc, product-engineering recommended me to clean it up using the workflow and credentials they've provided.

To be safe, it is a dry run, I'll create a new one if deleting with the dry run is successful.

Testing steps

We merge, and I run. Maybe will need to change the trigger, because there are some limitations about what branch Azure is accessible to us.

Follow-up issues

Remove -dryrun and do the cleanup.

Check during review

• Verify against Jira issue.
• Is the PR over 300 additions? Consider rejecting it with advice to split it. Is it over 500 additions? It should definitely be rejected.
• Unused code removed.
• Build passing.
• Is it a bug fix? Check that it is covered by a proper test (unit or integration).