Send only sender_pubkey instead of multisig_redeemscript in ContractTxInfoForSender(ReqContractSigsForSender)

[rishkwal]

Currently the ReqContractSigsForSender message sends the redeem script for the multisig funding transaction outputs to the maker here. The maker verifies whether their tweaked pubkey is present in the redeem script in this function and then signs the contract transaction.
A more optimized approach could be to just send the sender_pubkey instead of the multisig_redeemscript. The maker can then construct the redeem script from this sender_pubkey and their tweaked pubkey. If there is a mismatch/error in the contract transaction, an error would be thrown when signing the contract transaction.

[mojoX911]

Good idea. Marking this as v0.1.1 improvement.

One question would be. Are there multiple ways of constructing the reedemscript? Just a rearrangement, that keeps the script logic the same but invalidates the signature. If so then we need to ensure both parties create their local redeem script exactly the same way.

[rishkwal]

IMO the script construct must be standardized as a part of the protocol