Revert "Fix UTF-8 character boundary panic in DirectWrite text ... (#37767)" (#38800)

This reverts commit 9e7302520ec93a96a9b275a817f083b96620148e.

I run into an infinite hang in Zed nightly and used instruments and
activity monitor to sample what was going on. The root cause seemed to
be the unwrap_unchecked introduced in reverted PR.

Release Notes:

- N/A
2b283e7c53Anthony Eid committed on 9/24/2025, 4:44:39 PM· committed by GitHubparent45a4277
1 file changedLine totals unavailable