aws: key derivation fix and test case

[nbaws]

Commit Message: fix for sigv4a key derivation error and add test cases to cover Additional Description: Bug introduced (by me) in https://github.com/envoyproxy/envoy/pull/32487 Risk Level: Low Testing: Unit Docs Changes: N/A Release Notes: N/A Platform Specific Features: [Optional Runtime guard:] [Optional Fixes #Issue] [Optional Fixes commit #PR or SHA] [Optional Deprecated:] [Optional API Considerations:]

[suniltheta]

/assign nbaws

[repokitteh-read-only[bot]]

nbaws cannot be assigned to this issue.

:cat:

Caused by: a https://github.com/envoyproxy/envoy/pull/34377#issuecomment-2135795288 was created by @suniltheta.

see: more, trace.

[suniltheta]

/assign @nbaws

[repokitteh-read-only[bot]]

@nbaws cannot be assigned to this issue.

:cat:

Caused by: a https://github.com/envoyproxy/envoy/pull/34377#issuecomment-2135795949 was created by @suniltheta.

see: more, trace.

[nbaws]

/retest

[adisuissa]

@suniltheta @lavignes can you PTAL at the PR?

[nbaws]

Thanks for fixing this. Minor nits, but otherwise LGTM!

more fundamental fixes for this included. ty for your review!

[adisuissa]

Previously approved by @suniltheta (code-owner), merging.