Fix handling of controller CAN (#2049)

The key change is that before this commit "CAN received...triggering resend" immediately leads to outbound data "Sending (Command) message (Attempt 2".

After this PR then "CAN received...triggering resend will handle the incoming data "Unsolicited message received while waiting for ACK."

cpp/src/Driver.cpp

@@ -1723,7 +1723,8 @@ bool Driver::ReadMsg()
 				Log::Write(LogLevel_Warning, "m_currentMsg was NULL when trying to set MaxSendAttempts");
 				Log::QueueDump();
 			}
-			WriteMsg("CAN");
+			// Don't do WriteMsg("CAN"); here, the controller has data waiting to be handled by OZW.
+			// Instead, let the main loop handle incoming message first to flush the buffer(s)
 			break;
 		}