Gian chi 1732 followup

[GPaoloni]

Description

This PR addresses the following QA note:

Another question: in the empty state when no counsellors are available, how easy or difficult would it be to display text like “No counsellors are available right now”? Sorry this wasn’t explicitly stated in this ticket’s acceptance criteria. It’s a nice to have, not a release blocker.

Now, if there's no counselor available to transfer, the Agents tabs will be replaced as shown in the imaage.

Checklist

• Corresponding issue has been opened
• New tests added
• [n/a] Feature flags added
• Strings are localized
• [n/a] Tested for chat contacts
• [n/a] Tested for call contacts

Verification steps

• Make sure you are the only "available" counselor and try to transfer a task; you should see as in the image above.
• Repeat but with at least one other counselor "available"; the filtered list of "available" counselors should display.

[stephenhand]

This still relevant?