Add state_class total (#3608)

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

esphome/components/sensor/sensor.h

@@ -36,6 +36,7 @@ enum StateClass : uint8_t {
   STATE_CLASS_NONE = 0,
   STATE_CLASS_MEASUREMENT = 1,
   STATE_CLASS_TOTAL_INCREASING = 2,
+  STATE_CLASS_TOTAL = 3,
 };
 
 std::string state_class_to_string(StateClass state_class);