fix: update tests for Click 8.2 compatibility and local env isolation

[Sashwatdas123]

Details:

• Drop mix_stderr=False argument removed in Click 8.2
• Clear AWS_PROFILE before each test to prevent shell env leaking into CLI calls

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.04%. Comparing base (d9a7379) to head (ee57d3d).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #372   +/-   ##
=======================================
  Coverage   70.04%   70.04%           
=======================================
  Files          20       20           
  Lines        1876     1876           
=======================================
  Hits         1314     1314           
  Misses        562      562           

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