[wpilib] DriverStation: Change alliance station to use optional (#5229)

Many teams have issues trying to read the DS too early. By switching to an optional, we cause teams to check 2 things. Either 1) they explicitly check, and their code is correct, or 2) they just read .value() and their code reboots in a loop. However, because the DS will eventually connect, this 2nd case is ok, and should theoretically be undetectable on the field.

simulation/halsim_ws_core/src/main/native/cpp/WSProvider_DriverStation.cpp

@@ -84,6 +84,9 @@ void HALSimWSProviderDriverStation::RegisterCallbacks() {
           case HAL_AllianceStationID_kBlue3:
             station = "blue3";
             break;
+          case HAL_AllianceStationID_kUnknown:
+            station = "unknown";
+            break;
         }
         static_cast<HALSimWSProviderDriverStation*>(param)->ProcessHalCallback(
             {{">station", station}});