community: update documentation and model IDs for FriendliAI provider (#28984)
### Description
- In the example, remove `llama-2-13b-chat`,
`mixtral-8x7b-instruct-v0-1`.
- Fix llm friendli streaming implementation.
- Update examples in documentation and remove duplicates.
### Issue
N/A
### Dependencies
None
### Twitter handle
`@friendliai`