Crash when commiting after `open_commit_editor()`

[Jaehaks]

Describe the bug
After I edit some files using open_commit_editor and commit the file, gitui is crashed
If I edit message in native commit box intead of open_commit_editor(), the commit successed.
But It crashed always after I edit some file using open_commit_editor

To Reproduce
Steps to reproduce the behavior:

1. edit file in unstaged changes box
2. Press open_commit
3. Press open_commit_editor shortcut and edit additionally
4. close editor
5. Press commit shorcut
6. gitui is crashed and return to terminal

Screenshots
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Context (please complete the following information):

• Windows 10 Pro 22H2
• 0.28.0 (5527160)

Additional context
Add any other context about the problem here.