gpui: Pin to font-kit with improved OTC parsing performance. (#4047)

Details are in https://github.com/zed-industries/font-kit/pull/1; We're
not doing anything too fancy, really. Still, you should mostly see font
loading times drop significantly for font collections
Release Notes:
- Improved loading performance of large font collections (e.g. Iosevka).
Fixes https://github.com/zed-industries/community/issues/1745,
https://github.com/zed-industries/community/issues/246


https://github.com/zed-industries/zed/assets/24362066/f70edbad-ded6-4c12-9c6d-7a487f330a1b