Tefal Xplorer: make room_mode_switch optional

For compatibility with Rowenta X-Plorer S75 (rebranded model)

Discussion #2397

custom_components/tuya_local/devices/tefal_xplorer_vacuum.yaml

@@ -2,6 +2,8 @@ name: Tefal vacuum
 products:
   - id: gahugwuufkhzie7v
     name: Tefal X-plorer Serie 75 Animal
+  - id: tw2o6dntmqfpwsc7
+    name: Rowenta X-Plorer S75
 primary_entity:
   entity: vacuum
   dps:
@@ -159,6 +161,7 @@ primary_entity:
     - id: 139
       name: room_mode_switch
       type: boolean
+      optional: true
 secondary_entities:
   - entity: select
     name: Mode