Beok TGM50: make sensor selection optional

It seems some devices do not report dp 110.

Issue #1930

custom_components/tuya_local/devices/beok_tgm50_thermostat.yaml

@@ -205,6 +205,7 @@ secondary_entities:
       - id: 110
         type: string
         name: option
+        optional: true
         mapping:
           - dps_val: "1"
             value: Internal