Unmuted "???" print for mode read error

Arduino/src/main.cpp

@@ -618,7 +618,7 @@ void getReadableMode() {
     mode = "PKT  ";
     modeBase = modeByte;
   }
-  // else {             // removed this "else" to silence the intermittent ??? on the display
-  //   mode = "???";
-  // }
+  else {             // removed this "else" to silence the intermittent ??? on the display
+    mode = "???";
+  }
 }