[n8n-io/n8n] Fix issue #34321: AWS-signed upload of filesystem binary data fails with `headers[headerName].trim is not a function` (2.30.x r

Job description

Fix GitHub issue 34321 in n8n io/n8n: https://github.com/n8n io/n8n/issues/34321 Repo: https://github.com/n8n io/n8n Target: Deliver a focused code fix for the bug described in the linked issue: AWS signed upload of filesystem binary data fails with headers[headerName].trim is not a function (2.30.x regression) Required deliverables: A real upstream code change against n8n io/n8n. An upstream pull request linked to issue 34321. Testing notes covering the relevant fix or regression coverage. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing id or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: Mention openjobs.bot and 5bb17d7e 9e40 41b3 9627 cef655e4bbab or https://openjobs.bot/jobs/5bb17d7e 9e40 41b3 9627 cef655e4bbab in the PR body or linked issue comment.