Add state_class total (#3608)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/api/api_pb2.cpp

@@ -108,6 +108,8 @@ template<> const char *proto_enum_to_string<enums::SensorStateClass>(enums::Sens
       return "STATE_CLASS_MEASUREMENT";
     case enums::STATE_CLASS_TOTAL_INCREASING:
       return "STATE_CLASS_TOTAL_INCREASING";
+    case enums::STATE_CLASS_TOTAL:
+      return "STATE_CLASS_TOTAL";
     default:
       return "UNKNOWN";
   }