Change to device state attributes (#10536)

* Following the suggestion of @MartinHjelmare

homeassistant/components/sensor/serial.py

@@ -113,7 +113,7 @@ class SerialSensor(Entity):
         return False
 
     @property
-    def state_attributes(self):
+    def device_state_attributes(self):
         """Return the attributes of the entity (if any JSON present)."""
         return self._attributes