Closes #37601 

Regressed in https://github.com/zed-industries/zed/pull/36469. 

Edit: Original issue https://github.com/zed-industries/zed/issues/25744
is fixed for Zeta in this PR. For Copilot, it will be covered in a
follow-up. In the case of Copilot, even after discarding, we still get a
prediction on suggest, which is a bug.

Release Notes:

- Fixed issue where predict edit at cursor didn't work when
`show_edit_predictions` is `false`.