Vehicles: handle MSG_NAMED_FLOAT to fix ci failures

APMrover2/GCS_Mavlink.cpp

@@ -486,6 +486,7 @@ bool GCS_MAVLINK_Rover::try_send_message(enum ap_message id)
     case MSG_GIMBAL_REPORT:
     case MSG_RPM:
     case MSG_POSITION_TARGET_GLOBAL_INT:
+    case MSG_NAMED_FLOAT:
         break;  // just here to prevent a warning
     }
     return true;

AntennaTracker/GCS_Mavlink.cpp

@@ -271,6 +271,7 @@ bool GCS_MAVLINK_Tracker::try_send_message(enum ap_message id)
     case MSG_RPM:
     case MSG_MISSION_ITEM_REACHED:
     case MSG_POSITION_TARGET_GLOBAL_INT:
+    case MSG_NAMED_FLOAT:
         break; // just here to prevent a warning
     }
     return true;

ArduCopter/GCS_Mavlink.cpp

@@ -583,6 +583,8 @@ bool GCS_MAVLINK_Copter::try_send_message(enum ap_message id)
     case MSG_BATTERY_STATUS:
         send_battery_status(copter.battery);
         break;
+    case MSG_NAMED_FLOAT:
+        break;
     }
 
     return true;

ArduPlane/GCS_Mavlink.cpp

@@ -687,6 +687,8 @@ bool GCS_MAVLINK_Plane::try_send_message(enum ap_message id)
     case MSG_BATTERY_STATUS:
         send_battery_status(plane.battery);
         break;
+    case MSG_NAMED_FLOAT:
+        break;
     }
     return true;
 }