feat(commit): add '--allow-empty' flag to commit command

[AdrianDC]

Description

feat(commit): add '--allow-empty' flag to commit command

• Reworked over fix(commit): resolve 'always_signoff' configuration and '-s' CLI issues #1206 (commits follow-up)
• Reimplementation of Feature/allow empty commit #592, authorship preserved

Checklist

• Add test cases to all the changes you introduce
• Run ./scripts/format and ./scripts/test locally to ensure this change passes linter check and test
• Test the changes on the local machine manually
• Update the documentation for the changes

Expected behavior

Allow to invoke cz and create a commit without any change in it

Steps to Test This Pull Request

git cz c --allow-empty

Additional context

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.61%. Comparing base (120d514) to head (217e255).
Report is 414 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1217      +/-   ##
==========================================
+ Coverage   97.33%   97.61%   +0.27%     
==========================================
  Files          42       55      +13     
  Lines        2104     2519     +415     
==========================================
+ Hits         2048     2459     +411     
- Misses         56       60       +4     

Flag	Coverage Δ
unittests	97.61% <100.00%> (+0.27%)	⬆️

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[Lee-W]

Hi, thanks for contributing! would like to know why do we want --alow-empty. I thought we already have -- --allow-empty

[AdrianDC]

Coverage fixed 👍.

Lee-W, apart from regular usage, it's because the staging area checks fail :

 $ cz c --allow-empty
-Invalid commitizen arguments were found: `--allow-empty`. Please use -- separator for extra git args

 $ cz c -- --allow-empty
-No files added to staging!

 # =======================
 $ pipx uninstall commitizen; pipx install .
 uninstalled commitizen! ✨ 🌟 ✨
   installed package commitizen 3.29.0, installed using Python 3.12.3
   These apps are now globally available
     - cz
     - git-cz
 done! ✨ 🌟 ✨

 # =======================
 $ cz c --allow-empty
 ? Select the type of change you are committing feat: A new feature. Correlates with MINOR in SemVer
 ? What is the scope of this change? (class or file name): (press [enter] to skip)
  test
 ? Write a short and imperative summary of the code changes: (lower case and no period)
  test
 ? Provide additional contextual information about the code changes: (press [enter] to skip)
  
 ? Is this a BREAKING CHANGE? Correlates with MAJOR in SemVer No
 ? Footer. Information about Breaking Changes and reference issues that this commit closes: (press [enter] to skip)
 

 feat(test): test


 [master 6b9618c5] feat(test): test

+Commit successful!

[AdrianDC]

As discussed, I redid it all into -- --allow-empty support + implemented matching tests 👍.

Tested locally with cz c, cz c -- --allow-empty and cz c -s --allow-empty