Closes#38651
`git_panel.set_amend_pending(false, cx);` was being called before
`git_panel.commit_changes(...)` which was causing the commit buffer to
be cleared/reset before actually sending the commit request to git.
Introduced by #35268 which added clear buffer functionality to the
`set_amend_pending` function.
Release Notes:
- Fix git amend on panel sending "Update ..." instead of the original
commit message
- FIx git amend button not working
5212c66074