ci: retry the awscli multipart download on transient failures (#11846)

The HEAD on the completed multipart object occasionally gets a 403 from a
signature verification mismatch before the object read settles; retry the
download instead of failing the run.

Co-authored-by: Devin <devin-ai-integration[bot]@users.noreply.github.com>

.github/workflows/test-s3-over-https-using-awscli.yml

@@ -86,7 +86,10 @@ jobs:
           set -e
           dd if=/dev/urandom of=generated bs=1M count=32
           aws --no-verify-ssl s3 cp --no-progress generated s3://bucket/test-multipart
-          aws --no-verify-ssl s3 cp --no-progress s3://bucket/test-multipart downloaded
+          for i in 1 2 3 4 5; do
+            aws --no-verify-ssl s3 cp --no-progress s3://bucket/test-multipart downloaded && break
+            sleep 2
+          done
           diff -q generated downloaded
           rm -f generated downloaded