Update Amcrest component to SUPPORT_STREAM (#22553)

* Update camera.py

Update Amcrest component to SUPPORT_STREAM to allow streaming in the UI and Google Assistant.

* Update camera.py

homeassistant/components/amcrest/camera.py

@@ -2,7 +2,8 @@
 import asyncio
 import logging
 
-from homeassistant.components.camera import Camera
+from homeassistant.components.camera import (
+    Camera, SUPPORT_STREAM)
 from homeassistant.components.ffmpeg import DATA_FFMPEG
 from homeassistant.const import CONF_NAME
 from homeassistant.helpers.aiohttp_client import (
@@ -98,6 +99,11 @@ class AmcrestCam(Camera):
         """Return the name of this camera."""
         return self._name
 
+    @property
+    def supported_features(self):
+        """Return supported features."""
+        return SUPPORT_STREAM
+
     @property
     def stream_source(self):
         """Return the source of the stream."""