This changes the eth_getProof method implementation to re-encode the requested
storage keys, canonicalizing them in the response. For backwards-compatibility reasons,
go-ethereum accepts non-canonical hex keys. Accepting them is fine, but we should
not mirror invalid inputs into the output.

Closes #27306

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Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>