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/git_ui/src/commit_view.rs

@@ -356,7 +356,7 @@ async fn build_buffer_diff(
 
     cx.new(|cx| {
         let mut diff = BufferDiff::new(&buffer.text, cx);
-        diff.set_snapshot(diff_snapshot, &buffer.text, None, cx);
+        diff.set_snapshot(diff_snapshot, &buffer.text, cx);
         diff
     })
 }