Update ERC7913SignatureVerifierZKEmail.sol

Author: Amxx

contracts/utils/cryptography/ERC7913SignatureVerifierZKEmail.sol

@@ -2,8 +2,6 @@
 
 pragma solidity ^0.8.20;
 
-import {Strings} from "@openzeppelin/contracts/utils/Strings.sol";
-
 import {IDKIMRegistry} from "@zk-email/contracts/DKIMRegistry.sol";
 import {IVerifier} from "@zk-email/email-tx-builder/interfaces/IVerifier.sol";
 import {EmailAuthMsg} from "@zk-email/email-tx-builder/interfaces/IEmailTypes.sol";