fix(shorebird_cli): don't rely on display-friendly git status output

[bryanoltman]

Description

Uses git status --untracked-files=no --porcelain instead of git status to avoid reliance on a specific English-language string in console output.

Fixes #925.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🛠️ Bug fix (non-breaking change which fixes an issue)
• ❌ Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 Code refactor
• ✅ Build configuration change
• 📝 Documentation
• 🗑️ Chore

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (8eafd2b) 100.00% compared to head (23f1943) 100.00%.

❗ Current head 23f1943 differs from pull request most recent head f9a6d89. Consider uploading reports for the commit f9a6d89 to get more accurate results

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #934   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           78        78           
  Lines         2847      2845    -2     
=========================================
- Hits          2847      2845    -2     

Files Changed	Coverage Δ
...ib/src/validators/shorebird_flutter_validator.dart	100.00% <100.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[eseidel]

Now that trim will be carried forward by generations, wondering on what system they needed to trim. 🤣