remove required list from reverseshippingdetails since it has optional properties (Azure#21625)

Author: ashoknailwal

specification/databox/resource-manager/Microsoft.DataBox/stable/2022-09-01/databox.json

@@ -5264,10 +5264,6 @@
     },
     "ReverseShippingDetails": {
       "description": "Reverse Shipping Address and contact details for a job.",
-      "required": [
-        "contactDetails",
-        "shippingAddress"
-      ],
       "type": "object",
       "properties": {
         "contactDetails": {