assistant2: Make `Esc` cancel current completion (#23076)

This PR makes it so pressing `Esc` in Assistant2 will cancel the current
completion.

Release Notes:

- N/A
c1c767a5bdMarshall Bowers committed on 1/13/2025, 7:09:27 PM· committed by GitHubparentb59a9f1
3 files changedLine totals unavailable