feat: Add Additional Custom Errors for MultiSigContractV2

src/MultiSigContractV2.sol

@@ -24,4 +24,9 @@ contract MultiSigContractV2 is Ownable, ReentrancyGuard, Pausable {
     error MultiSigContract__OnlyFactoryTokenContract();
     error MultiSigContract__OnlySigner();
     error MultiSigContract__AlreadySigned();
+    error MultiSigContract__NotSigned();
+    error MultiSigContract__InvalidTransaction();
+    error MultiSigContract__TransactionExpired();
+    error MultiSigContract__TransactionNotReady();
+    error MultiSigContract__InvalidSignerCount();
 }