Studio: Fix incorrect offline message displayed alongside "delete site" link

[katinthehatsite]

Closes https://github.com/Automattic/dotcom-forge/issues/7144

Proposed Changes

This PR does the following:

• it allows to delete a local site that does not have any demo sites when the user is offline
• it adjusts the offline message on the Delete site link to be displayed only when the user has a local site with snapshots

Testing Instructions

• Pull the changes from this branch
• Start the app with nvm use && npm install && npm start
• Create a local site
• Create a second local site and add a demo site for this one
• Disable your device's internet connection (in my case, I disabled WIFI)
• Navigate to Settings tab for a local site that has a demo site associated with it
• Observe that the Delete site link is disabled and the offline message appears:

• Navigate to another local site that does not have a demo site associated with it
• Observe that the Delete site link is available under Settings tab
• Click on Delete site
• Confirm that the local site was deleted

Pre-merge Checklist

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

[kozer]

I tested it and works as expected! ( However I left a comment, as things can be simplified )

[kozer]

@katinthehatsite , while I was testing it, I found a bug! It's not related to you ( Happens on the trunk as well ). I'll approve! Nice work!
( Wojtek asked from team Sparrow to review it as well, so let's wait )

[SiobhyB]

This works perfectly for me, thanks for fixing Kat 🙌