fix(anthropic): replace retired model IDs in tests and docstrings (#35365)

## Summary

- Replace `claude-3-5-haiku-20241022` and `claude-3-7-sonnet-20250219`
with `claude-haiku-4-5-20251001` and `claude-sonnet-4-5-20250929`
respectively
- Both models were retired by Anthropic on February 19, 2026, causing
all anthropic integration tests to fail
- Updates integration tests, a unit test, and docstring examples in
`langchain-core`

See:
https://platform.claude.com/docs/en/docs/resources/model-deprecations