assistant2: Add prompt editor (#23436)

This PR adds the Assistant1 experience to Assistant2 as a "prompt
editor".

<img width="1309" alt="Screenshot 2025-01-21 at 7 17 26 PM"
src="https://github.com/user-attachments/assets/3ce2f32b-2b1a-48a8-8e56-4c44e3ac4ce5"
/>

Release Notes:

- N/A

Marshall Bowers committed 1y ago

e59c9108455fa4a51ed3eb2ed6b4cf3fe268b122

Parent: 3d47f32

Committed by GitHub <noreply@github.com> on 1/22/2025, 12:36:55 AM