Changes to List frequencies

removed the optional property data/items/billingPolicy from the response with the 200 status

removed the optional property data/items/deliveryPolicy from the response with the 200 status

api operation id list-available-frequencies removed and replaced with list-frequencies

for the path request parameter subscriptionId, the format was generalized from int32 to int64

added the non-success response with the status 400

added the optional property data/items/billingInterval to the response with the 200 status

added the optional property data/items/billingIntervalCount to the response with the 200 status

added the optional property data/items/deliveryInterval to the response with the 200 status

added the optional property data/items/deliveryIntervalCount to the response with the 200 status