Camnsmart E27: mark more dps optional

Device is only reporting SD card capacity, everything else needs
to be optional.
 Issue #1336

custom_components/tuya_local/devices/camnsmart_e27_camera.yaml

@@ -159,6 +159,7 @@ secondary_entities:
       - id: 158
         type: integer
         name: brightness
+        optional: true
         range:
           min: 1
           max: 100
@@ -252,6 +253,7 @@ secondary_entities:
       - id: 173
         type: integer
         name: value
+        optional: true
         unit: s
         range:
           min: 0