Improve Error Messaging for APOC Procedure Failure in Neo4jGraph (lan…

…gchain-ai#5547)

## Improve Error Messaging for APOC Procedure Failure in Neo4jGraph

This commit revises the error message provided when the
'apoc.meta.data()' procedure fails. Previously, the message simply
instructed the user to install the APOC plugin in Neo4j. The new error
message is more specific.

Also removed an unnecessary newline in the Cypher statement variable:
`node_properties_query`.

Fixes langchain-ai#5545 

## Who can review?
  - @vowelparrot
  - @dev2049

langchain/graphs/neo4j_graph.py

@@ -62,7 +62,8 @@ def __init__(
         except neo4j.exceptions.ClientError:
             raise ValueError(
                 "Could not use APOC procedures. "
-                "Please install the APOC plugin in Neo4j."
+                "Please ensure the APOC plugin is installed in Neo4j and that "
+                "'apoc.meta.data()' is allowed in Neo4j configuration "
             )
 
     @property