git_ui: Fix utf8 panic in `compress_commit_diff` (#43972)

Fixes ZED-3QG

Release Notes:

- N/A *or* Added/Fixed/Improved ...
8d09610748Lukas Wirth committed on 12/2/2025, 8:31:44 AM· committed by GitHubparent5b6663e
1 file changedLine totals unavailable