Support UTF-8 explicit signature at start of JSON file served from public_jwk_url (LTI Developer Configuration)

[PinkDuck]

Describe the bug

With UTF-8 byte-order marker (BOM):
Identity server error: BadRequest
{"error":"invalid_request","error_description":"JWK Error: Invalid JSON"}

Without:
200 Success

During client_credentials OAuth2 JWT token request.

Screenshots or screen recordings

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Steps to reproduce

No response

What browsers are you seeing the problem on (if applicable)?

No response

Backtrace

Relevant log output