fix(cloudformation): Support S3 URLs with region names

[sanathkr]

Fixes #4363

Issue #, if available:

Description of changes:

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[codecov-io]

Codecov Report

Merging #4402 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #4402   +/-   ##
========================================
  Coverage    94.51%   94.51%           
========================================
  Files          188      188           
  Lines        14168    14168           
========================================
  Hits         13391    13391           
  Misses         777      777

Impacted Files	Coverage Δ
...customizations/cloudformation/artifact_exporter.py	98.61% <ø> (ø)	⬆️

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