Fix post-commit clang-format exit handling

[paulromano]

Description

This PR makes a small fix in the bundled post-commit hook for running clang-format. Namely, git-clang-format returns the exit status 1 after a successful formatting update, so the hook should only treat statuses > 1 as a true error. Accounting for this allows the post-commit hook to stage formatting changes and amend the commit as intended. Previously, set -e caused the hook to exit when git-clang-format applied changes, leaving the commit unformatted and the working tree modified.

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 18) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[GuySten]

LGTM.