fix: signTransaction updated to work with latest v5 SDK

[d4mr]

PR-Codex overview

This PR focuses on enhancing the sign-transaction functionality by incorporating the thirdwebClient, updating the transaction handling logic, and utilizing the prepareTransaction and toSerializableTransaction methods for improved transaction preparation and serialization.

Detailed summary

• Replaced toTransactionType import with thirdwebClient.
• Added imports for prepareTransaction, toSerializableTransaction, and getChain.
• Updated chainId definition to be of type Integer.
• Modified request handling to destructure chainId, nonce, and transaction.
• Introduced chain variable using getChain.
• Updated account retrieval to use dynamic chainId.
• Created prepareTransactionOptions object with updated transaction handling.
• Used prepareTransaction and toSerializableTransaction for transaction preparation and serialization.

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[joaquim-verges]

Is this gonna break existing users calling without a chain id?

[d4mr]

yes, open to any way to support pre-eip155 signatures as well. I couldn't find a way with the current SDK.

[joaquim-verges]

Tbh signing a tx without a chain id is kinda sus. And I guess it will only break ppl when they upgrade?

Maybe we make it really clear in the release notes

[d4mr]

A lot of this gets much better with zod schemas, so I have not invested much into make the validation super air tight here (updating to hexSchema etc)