Make all json parsing less strict by default (#15287)

- Enables strict=False by default
- Uses partial json recovery logic by default

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libs/langchain/langchain/evaluation/parsing/base.py

@@ -1,4 +1,5 @@
 """Evaluators for parsing strings."""
+import json
 from operator import eq
 from typing import Any, Callable, Optional, Union, cast
 
@@ -68,7 +69,7 @@ class JsonValidityEvaluator(StringEvaluator):
 
         """
         try:
-            parse_json_markdown(prediction)
+            parse_json_markdown(prediction, parser=json.loads)
             return {"score": 1}
         except Exception as e:
             return {"score": 0, "reasoning": str(e)}