fix(instrumentation): Enable downstream instruments in LangChain

[thisthat]

Signed-off-by: Giovanni Liva [email protected]

• [ ] I have added tests that cover my changes.
• [x] If adding a new instrumentation or changing an existing one, I've added screenshots from some observability platform showing the change.
• [x] PR name follows conventional commits format: feat(instrumentation): ... or fix(instrumentation): ....
• [ ] (If applicable) I have updated the documentation accordingly.

Before

After

Fixes #2271

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