post https://api.circle.com/v1/w3s/user/sign/message
Generates a challenge for signing the EIP-191 message from a specified user-controlled wallet. Please note that not all the Dapps currently support Smart Contract Account (SCA), the difference between EOA and SCA can be found in the account types guide, and you can check the list of Dapps that support SCA: https://eip1271.io/.
