fix: json load diff regression downstream

Author: YOU54F

lib/pact/consumer_contract/consumer_contract.rb

@@ -48,10 +48,7 @@ def self.from_hash(hash)
     end
 
     def self.from_json string
-      deserialised_object = JSON.load(
-        maintain_backwards_compatiblity_with_producer_keys(string),
-        nil, { create_additions: false }
-      )
+      deserialised_object = JSON.unsafe_load(maintain_backwards_compatiblity_with_producer_keys(string))
       from_hash(deserialised_object)
     end