Fix signer key requests example implementations

[seanrobenalt]

Updates poll function response to make sure the signedKeyRequest key is accessed, allowing the state check to proceed and enter the completed block.

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PR-Codex overview

This PR updates the code to access the signedKeyRequest property from the response data result in warpcast/signers.md and warpcast/signer-requests.md.

Detailed summary

• Updated code to access signedKeyRequest property in response data result for signers and signer requests.

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[vercel]

@seanrobenalt is attempting to deploy a commit to the farcaster Team on Vercel.

A member of the Team first needs to authorize it.

[sds]

Thank you