Update dialogflow.markdown (#13951)

Dialogflow returns values with   instead of space between words. replace(' ', '_') doesn't work. Oddly neither does replace(' ', '_'), I assume some characters are getting escaped. Added striptags filter to make it work.

source/_integrations/dialogflow.markdown

@@ -111,6 +111,6 @@ intent_script:
             switch.turn_off
           {%- endif -%}
         data_template:
-          entity_id: "switch.light_{{ Room | replace(' ', '_') }}"
+          entity_id: "switch.light_{{ Room | striptags | replace(' ', '_') }}"
 ```
 {% endraw %}