feat(cli-integ): speed up image pulls by logging into ECR public

[iliapolo]

Porting aws/aws-cdk-cli-testing#84

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.11%. Comparing base (c7fafb2) to head (daf8f87).
⚠️ Report is 232 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #400      +/-   ##
==========================================
+ Coverage   79.88%   80.11%   +0.23%     
==========================================
  Files          66       66              
  Lines        6879     6879              
  Branches      782      788       +6     
==========================================
+ Hits         5495     5511      +16     
+ Misses       1364     1345      -19     
- Partials       20       23       +3     

Flag	Coverage Δ
suite.unit	80.11% <ø> (+0.23%)	⬆️

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