community[patch]: root validator set explicit pre=False or pre=True (#23764)

See issue: https://github.com/langchain-ai/langchain/issues/22819

libs/community/langchain_community/utilities/arxiv.py

@@ -72,7 +72,7 @@ class ArxivAPIWrapper(BaseModel):
                 return False
         return True
 
-    @root_validator()
+    @root_validator(pre=True)
     def validate_environment(cls, values: Dict) -> Dict:
         """Validate that the python package exists in environment."""
         try: