fix(cdk-assets): remove https from endpoint, to work with podman

[janmeier]

Fixes aws/aws-cdk#16209

Redo of aws/aws-cdk#28926

podman does not allow prefixing the endpoint with https when calling docker login:

fail: docker login --username AWS --password-stdin https://XXX.dkr.ecr.eu-west-1.amazonaws.com exited with error code 125: Error: credentials key has https[s]:// prefix

This PR removes the prefix, which works with both docker and podman

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[janmeier]

@kaizencc ping

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.81%. Comparing base (bd02059) to head (065a829).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #92      +/-   ##
==========================================
+ Coverage   84.70%   84.81%   +0.10%     
==========================================
  Files         204      204              
  Lines       35647    35647              
  Branches     4594     4622      +28     
==========================================
+ Hits        30194    30233      +39     
+ Misses       5299     5260      -39     
  Partials      154      154              

Flag	Coverage Δ
suite.unit	84.81% <100.00%> (+0.10%)	⬆️

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