fix: Remove obsolete preprocess step

preprocess.py

@@ -131,18 +131,6 @@
 }
 logging.info(f"Added schema for 200 response of /status/ get")
 
-# NOTE: below fixed upstream
-# change model IPAddress's assigned_object property from string to object otherwise it fails to unmarshall
-data["definitions"]["IPAddress"]["properties"]["assigned_object"] = {
-    "title": "Assigned object",
-    "type": "object",
-    "readOnly": True,
-}
-logging.info(
-    f"Fix 'error: json: cannot unmarshal number into Go struct field IPAddress.assigned_object of type \
-string' when creating available-ips"
-)
-
 # Change model returned by paths /available-ips/ from AvailableIP to IPAddress.
 data["paths"]["/ipam/ip-ranges/{id}/available-ips/"]["post"]["responses"]["201"][
     "schema"