fix(shorebird_cli): detect Azure pipeline CI environment

[bryanoltman]

Description

Adds a check for the TF_BUILD environment variable in our isRunningOnCi check, which is set by the Azure pipeline environment.

Fixes #1809

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

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (0d67bfb) to head (b215874).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1811   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          167       167           
  Lines         5306      5307    +1     
=========================================
+ Hits          5306      5307    +1     

Flag	Coverage Δ
shorebird_cli	100.00% <100.00%> (ø)

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