h-a: Remove roomba_is_downstairs template sensor

This sensor is now provided by a [Threshold][0] helper.

[0]: https://www.home-assistant.io/integrations/threshold/

home-assistant/configuration.yaml

@@ -269,19 +269,6 @@ switch:
   mac: e0:d5:5e:6e:ad:ac
   broadcast_address: 172.30.0.63
 
-binary_sensor:
-- platform: template
-  sensors:
-    roomba_is_downstairs:
-      friendly_name: Roomba is Downstairs
-      value_template: >-
-        {% if is_state('binary_sensor.roomba_ibeacon_ble_presence', 'on') and
-              states('sensor.roomba_ibeacon_ble_rssi') | float > -70 %}
-        on
-        {% else %}
-        off
-        {% endif %}
-
 prometheus:
   filter:
     exclude_entity_globs: