fix: check whether xattr is changed before and after clear

[Lee-W]

Fixes #56

Describe your changes

Why
Some extend attributes cannot be removed in certain setups on macOS, which would cause
the file being modified meaninglessly

Checklist

• Test cases have been modified/added to cover any code changes.
• Docstrings have been modified/created for any code changes.
• All linting and formatting checks pass (see the contributing guidelines for more information).

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 76.19048% with 5 lines in your changes missing coverage. Please review.

Project coverage is 95.90%. Comparing base (d387c8b) to head (7a4cf48).
Report is 2 commits behind head on main.

❗ Current head 7a4cf48 differs from pull request most recent head 6b471d3

Please upload reports for the commit 6b471d3 to get more accurate results.

Files with missing lines	Patch %	Lines
tests/test_cli.py	72.72%	3 Missing ⚠️
src/exif_stripper/__init__.py	80.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main      #57      +/-   ##
===========================================
- Coverage   100.00%   95.90%   -4.10%     
===========================================
  Files            3        3              
  Lines          105      122      +17     
===========================================
+ Hits           105      117      +12     
- Misses           0        5       +5     

Files with missing lines	Coverage Δ
src/exif_stripper/__init__.py	93.75% <80.00%> (-6.25%)	⬇️
tests/test_cli.py	96.05% <72.72%> (-3.95%)	⬇️

[stefmolin]

Thanks, @Lee-W!