Add support for Sensor state class (#1835)

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

esphome/components/uptime/sensor.py

@@ -1,13 +1,21 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import sensor
-from esphome.const import CONF_ID, DEVICE_CLASS_EMPTY, UNIT_SECOND, ICON_TIMER
+from esphome.const import (
+    CONF_ID,
+    DEVICE_CLASS_EMPTY,
+    STATE_CLASS_NONE,
+    UNIT_SECOND,
+    ICON_TIMER,
+)
 
 uptime_ns = cg.esphome_ns.namespace("uptime")
 UptimeSensor = uptime_ns.class_("UptimeSensor", sensor.Sensor, cg.PollingComponent)
 
 CONFIG_SCHEMA = (
-    sensor.sensor_schema(UNIT_SECOND, ICON_TIMER, 0, DEVICE_CLASS_EMPTY)
+    sensor.sensor_schema(
+        UNIT_SECOND, ICON_TIMER, 0, DEVICE_CLASS_EMPTY, STATE_CLASS_NONE
+    )
     .extend(
         {
             cv.GenerateID(): cv.declare_id(UptimeSensor),