Update deprecated Neo4jGraph import to support langchain-neo4j

[TheCommandCat]

Description

This PR addresses the following deprecation warning encountered during execution of the Graph Memory module in mem0:

LangChainDeprecationWarning: The class Neo4jGraph was deprecated in LangChain 0.3.8 and will be removed in 1.0. An updated version of the class exists in the langchain-neo4j package and should be used instead. To use it run pip install -U langchain-neo4j and import as from langchain_neo4j import Neo4jGraph.

Previously, using graph_memory.py triggered this warning during initialization:

\Lib\site-packages\mem0\memory\graph_memory.py:42: LangChainDeprecationWarning: The class `Neo4jGraph` was deprecated in LangChain 0.3.8 and will be removed in 1.0.
  self.graph = Neo4jGraph(

Fix Overview

The changes in \mem0\memory\graph_memory.py update the import to the new langchain-neo4j package while maintaining backward compatibility with langchain-community.

Old Import:

try:
    from langchain_community.graphs import Neo4jGraph
except ImportError:
    raise ImportError("langchain_community is not installed. Please install it using pip install langchain-community")

New Import:

try:
    from langchain_neo4j import Neo4jGraph
except ImportError:
    try:
        from langchain_community.graphs.neo4j_graph import Neo4jGraph
    except ImportError:
        raise ImportError(
            "Neither 'langchain-neo4j' nor 'langchain-community' is installed. "
            "Please install one using 'pip install langchain-neo4j' or 'pip install langchain-community'."
        )

This ensures compatibility with both the new langchain-neo4j package and the older langchain-community package, eliminating the deprecation warning.

BTW - building poetry also upgraded poetry.lock any available packages by itself, I'm not very familiar yet with poetry so will free to remove that if not necessary :)

Type of change

Please delete options that are not relevant.

• Refactor (does not change functionality, e.g. code style improvements, linting)

How Has This Been Tested?

I wrote a simple script that just init mem0 calss with a local ollama llm, chromadb and neo4j, before the fix the warning popup was displayed and now it dosent

Please delete options that are not relevant.

• Test Script (please provide)

from mem0 import Memory

config = {
        "embedder": {
            "provider": "ollama",
            "config": {
                "model": "mxbai-embed-large"
            }
        },
        "llm": {
        "provider": "ollama",
        "config": {
            "model": "llama3.2",
            }
        },
        "vector_store": {
            "provider": "chroma",
            "config": {
                "collection_name": "VectorStore",
                "path": "db",
            }
        },
        "graph_store": {
            "provider": "neo4j",
            "config": {
                "url": "bolt://localhost:7687",
                "username": "neo4j",
                "password": "yourpassword"
            }
        },
        "version": "v1.1"
}

m = Memory.from_config(config)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas (self explanatory)
• I have made corresponding changes to the documentation (not needed as much as I know)
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works (not needed)
• New and existing unit tests pass locally with my changes (locally i got errors on testing but no new ones with this changes)
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

Maintainer Checklist

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Made sure Checks passed

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