Feat: add basic Langfuse support for LLM module (#6443)
### What problem does this PR solve?
#6155
Add basic Langfuse support for LLM module.
A trace example:
<img width="755" alt="image"
src="https://github.com/user-attachments/assets/25c1f852-5116-486c-a47f-6097187142ca"
/>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
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