Deprecate langchain-arcade #2456

Job	Run time
setup	5s
test-toolkits (math)	1s
test-toolkits (brightdata)	1s
test-toolkits (linkedin)	1s
test-toolkits (zendesk)	1s
test-toolkits-with-gha-secrets (mongodb)	15m 3s
test-toolkits-with-gha-secrets (clickhouse)	1s
test-toolkits-with-gha-secrets (postgres)	15m 3s
	30m 16s

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