errorCode should reflect the state of the MMU

If the protocol reports and error and give errorCode
a value. When the error is resolved, errorCode is not reset to OK.

If the MMU is not in an error state I would expect errorCode to reflect that.

This fixes MMUCurrentErrorCode()

Change in memory:
Flash: +12 bytes
SRAM: 0 bytes

Firmware/mmu2_protocol_logic.cpp

@@ -365,6 +365,7 @@ StepStatus ProtocolLogic::ProcessCommandQueryResponse() {
         // It can also be an X0 F which means MMU just successfully restarted.
         if (ReqMsg().code == rsp.request.code && ReqMsg().value == rsp.request.value) {
             progressCode = ProgressCode::OK;
+            errorCode = ErrorCode::OK;
             scopeState = ScopeState::Ready;
             rq = RequestMsg(RequestMsgCodes::unknown, 0); // clear the successfully finished request
             return Finished;