fix: Do not assert special tx type for cbtx in simplified mn list difff output

Author: UdjinM6

src/evo/simplifiedmns.cpp

@@ -279,7 +279,8 @@ UniValue CSimplifiedMNListDiff::ToJson(bool extended) const
     }
     obj.pushKV("newQuorums", newQuorumsArr);
 
-    if (const auto opt_cbTxPayload = GetTxPayload<CCbTx>(*cbTx)) {
+    // Do not assert special tx type here since this can be called prior to DIP0003 activation
+    if (const auto opt_cbTxPayload = GetTxPayload<CCbTx>(*cbTx, false)) {
         obj.pushKV("merkleRootMNList", opt_cbTxPayload->merkleRootMNList.ToString());
         if (opt_cbTxPayload->nVersion >= CCbTx::Version::MERKLE_ROOT_QUORUMS) {
             obj.pushKV("merkleRootQuorums", opt_cbTxPayload->merkleRootQuorums.ToString());