[chore] Add x-amzn-requestid as source for aws.request_id

[Flarna]

Changes

The response headers used by AWS SDK are x-amzn-requestid, x-amzn-request-id or x-amz-request-id.

see e.g. here and here or here.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.

[lmolkova]

Thanks!