Fixes to SelfQueryRetriever and LLMRouterChain deprecation warning #4565

Job	Run time
Python 3.8 extended tests	5m 14s
Python 3.9 extended tests	4m 37s
Python 3.10 extended tests	4m 20s
Python 3.11 extended tests	5m 27s
lint / build (3.8)	3m 30s
lint / build (3.11)	3m 22s
test / Python 3.8	1m 46s
pydantic-compatibility / Pydantic v1/v2 compatibility - Python 3.8	1m 44s
pydantic-compatibility / Pydantic v1/v2 compatibility - Python 3.9	1m 52s
test / Python 3.9	1m 50s
pydantic-compatibility / Pydantic v1/v2 compatibility - Python 3.10	1m 48s
test / Python 3.10	2m 11s
pydantic-compatibility / Pydantic v1/v2 compatibility - Python 3.11	3m 33s
test / Python 3.11	1m 39s
	42m 53s

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