langchain-mistralai[major]: Add MistralAI chat and embed #8361

Job	Run time
Check linting	3m 23s
Unit Tests (ubuntu-latest, 18.x)	3m 30s
Unit Tests (ubuntu-latest, 20.x)	3m 22s
test-exports / exports-esbuild	4m 35s
test-exports / exports-esm	4m 47s
test-exports / exports-cjs	4m 30s
test-exports / exports-cf	4m 18s
test-exports / exports-vercel	4m 59s
test-exports / exports-vite	4m 15s
	37m 39s

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