fix(ilife_v20_vacuum): make do not disturb switch optional

The last two vacuums requested (one an iLife V30 that would match
this better than the current lefant best match), have this switch on
the same dp, but it is not in the log. Likely this model also doesn't
always report this.

Issue #4715

custom_components/tuya_local/devices/ilife_v20_vacuum.yaml

@@ -366,6 +366,7 @@ entities:
     dps:
       - id: 25
         type: boolean
+        optional: true
         name: switch
 
   - entity: switch