Not compatible with langchain-core>=0.3.79

Error message:
ModuleNotFoundError: No module named 'langchain_core.pydantic_v1'

Fix was to downgrade to langchain-core==0.3.79

Invoked by from databricks_langchain import ChatDatabricks
Stack trace:

     17 from databricks.sdk import WorkspaceClient
     18 from pydantic import BaseModel
File /local_disk0/.ephemeral_nfs/envs/pythonEnv-90c00629-c40f-4608-96d6-3c5713086415/lib/python3.12/site-packages/databricks_langchain/__init__.py:18
     16 from unitycatalog.ai.core.base import set_uc_function_client
     17 from unitycatalog.ai.core.databricks import DatabricksFunctionClient
---> 18 from unitycatalog.ai.langchain.toolkit import UCFunctionToolkit, UnityCatalogTool
     20 from databricks_langchain.chat_models import ChatDatabricks
     21 from databricks_langchain.embeddings import DatabricksEmbeddings
File /local_disk0/.ephemeral_nfs/envs/pythonEnv-90c00629-c40f-4608-96d6-3c5713086415/lib/python3.12/site-packages/unitycatalog/ai/langchain/toolkit.py:13
      6 from langchain_core._api.deprecation import LangChainDeprecationWarning
      8 warnings.filterwarnings(
      9     "ignore",
     10     message=r".*As of langchain-core 0\.3\.0, LangChain uses pydantic v2 internally.*",
     11     category=LangChainDeprecationWarning,
     12 )
---> 13 from langchain_core.pydantic_v1 import BaseModel, Field, root_validator
     14 from langchain_core.tools import StructuredTool
     16 from unitycatalog.ai.core.base import BaseFunctionClient

Start with databricks_langchain/init.py and the import path through unitycatalog/ai/langchain/toolkit.py when importing ChatDatabricks. Check the langchain-core compatibility around version 0.3.79 and the pydantic_v1 import, then verify that ChatDatabricks imports successfully with langchain-core >=0.3.79.