Make Jewish Calendar use DEVICE_CLASS_TIMSTAMP and remove timestamp attribute (#41397)

* Added "time" attribute

* Revert "Added "time" attribute"

This reverts commit 8adab9b78814aa1bc2adca242278e66ee9dd0b7f.

* Make DEVICE_CLASS use the DEVICE_CLASS_TIMESTAMP

* Removed unix timstamp attr

* keep attributes but delete the timestamp

homeassistant/components/jewish_calendar/sensor.py

@@ -3,7 +3,7 @@ import logging
 
 import hdate
 
-from homeassistant.const import SUN_EVENT_SUNSET
+from homeassistant.const import DEVICE_CLASS_TIMESTAMP, SUN_EVENT_SUNSET
 from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.sun import get_astral_event_date
 import homeassistant.util.dt as dt_util
@@ -150,7 +150,7 @@ class JewishCalendarTimeSensor(JewishCalendarSensor):
     @property
     def device_class(self):
         """Return the class of this sensor."""
-        return "timestamp"
+        return DEVICE_CLASS_TIMESTAMP
 
     @property
     def device_state_attributes(self):
@@ -160,8 +160,6 @@ class JewishCalendarTimeSensor(JewishCalendarSensor):
         if self._state is None:
             return attrs
 
-        attrs["timestamp"] = self._state.timestamp()
-
         return attrs
 
     def get_state(self, daytime_date, after_shkia_date, after_tzais_date):