up arrow to edit last comment does not work on work items

To reproduce:

1. Go to an issue and ensure you are not using the "New issue look"
2. Write a comment
3. Focus the new comment input
4. hit the up arrow on your keyboard
5. Focus will move to your most recent comment and it will be in the edit state
6. Now turn on the "New issue look" toggle so that the issue is rendered as a work item
7. Focus the new comment input again
8. hit the up arrow on your keyboard
9. Nothing will happen. This functionality is not implemented for work items.