Fix diff recalculation hang (#28377)

Fixes https://github.com/zed-industries/zed/issues/26039

Release Notes:

- Fixed an issue where diffs stopped updating closing and reopening them
after staging hunks.
- Fixed a bug where staging a hunk while the cursor was in a deleted
line would move the cursor erroneously.

---------

Co-authored-by: Cole Miller <m@cole-miller.net>
Co-authored-by: João Marcos <marcospb19@hotmail.com>

crates/assistant_tool/src/action_log.rs

@@ -235,7 +235,7 @@ impl ActionLog {
                     .await;
 
                 diff.update(cx, |diff, cx| {
-                    diff.set_snapshot(diff_snapshot, &buffer_snapshot, None, cx)
+                    diff.set_snapshot(diff_snapshot, &buffer_snapshot, cx)
                 })?;
             }
             this.update(cx, |this, cx| {