Tongou QCB2: make compatible with QCB2-CB model

This model is missing the earth leakage detection (already optional) and
neutral temperature (needed to be made optional).

No product id supplied, so no product details added.

Issue #2642

custom_components/tuya_local/devices/tongou_qcb2_circuitbreaker.yaml

@@ -500,6 +500,7 @@ entities:
     dps:
       - id: 134
         type: integer
+        optional: true
         name: sensor
         unit: C
         class: measurement