openai[patch]: update imports in test (#30828)

Quick fix to unblock CI, will need to address in core separately.

Author: ccurme

libs/partners/openai/tests/unit_tests/test_load.py

@@ -1,5 +1,4 @@
-from langchain_core.load.dump import dumpd, dumps
-from langchain_core.load.load import load, loads
+from langchain_core.load import dumpd, dumps, load, loads
 
 from langchain_openai import ChatOpenAI, OpenAI