fix: Remove context passed to MinIO's NewSSEKMS

[lbeckman314]

Overview 🌀

This PR adds a fix to Funnel to resolve a malformed x-amz-server-side-encryption-context header when using SSE-KMS with the MinIO Go client (Issue #2235).

Current Behavior ⚠️

• encrypt.NewSSEKMS(kmskeyId, ctx) was called with a context.Context as the second argument (the KMS encryption context).

• Since NewSSEKMS JSON-marshals whatever is passed, this produced a nested object {"Context":{"Context":{"Context":{}}}} which was base64-encoded into the x-amz-server-side-encryption-context header.

• S3 rejects this because it requires a flat string-string map, causing upload/download failures on KMS-enabled buckets.

New Behavior ✔️

• encrypt.NewSSEKMS(kmskeyId, nil) is called instead.

• Passing nil tells the MinIO client to omit the x-amz-server-side-encryption-context header entirely, which is correct when no additional KMS encryption context key-value pairs are needed.

Breaking Changes? ❌

• No breaking change. This is a bug fix that resolves current issues with KMS-enabled buckets — the malformed header caused errors. Users who were not using KMS (KmsKeyID left empty) are unaffected.

[github-actions]

Gen3 Integration Tests

filepath	passed	skipped	SUBTOTAL
tests/test_gen3_workflow.py	25	4	29
TOTAL	25	4	29

[github-actions]

Gen3 Integration Tests

filepath	passed	skipped	SUBTOTAL
tests/test_gen3_workflow.py	25	4	29
TOTAL	25	4	29

[github-actions]

Gen3 Integration Tests

filepath	passed	skipped	SUBTOTAL
tests/test_gen3_workflow.py	25	4	29
TOTAL	25	4	29

[github-actions]

Gen3 Integration Tests

filepath	passed	skipped	SUBTOTAL
tests/test_gen3_workflow.py	25	4	29
TOTAL	25	4	29

[github-actions]

Gen3 Integration Tests

filepath	passed	skipped	SUBTOTAL
tests/test_gen3_workflow.py	25	4	29
TOTAL	25	4	29