Allow site deletion in offline mode by skipping Preview sites cleanup

[ivan-ottinger]

Related issues

• Resolves STU-659

Proposed Changes

• allow local Studio site deletion when offline while skipping preview site cleanup

Testing Instructions

1. Check out the PR branch and build the app with npm start.
2. Create a preview site for one of your local Studio site.
3. Go offline (e.g. by disabling wifi).
4. Try to delete the local Studio site with linked preview site.
5. The local site should get deleted without triggering preview site deletion (i.e. there should be no "Deleting preview site failed" error displayed in the UI and when you navigate to the Usage tab in the app Settings, the preview site should still be counted to the total limit)

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[epeicher]

Thanks for improving this Ivan! I can confirm that I am able to delete my site and I see the preview site counted to the total limit. LGTM!