* fix(langfuse_prompt_management.py): migrate dynamic logging to langfuse custom logger compatible class
* fix(langfuse_prompt_management.py): support failure callback logging to langfuse as well
* feat(proxy_server.py): support setting custom tokenizer on config.yaml
Allows customizing value for `/utils/token_counter`
* fix(proxy_server.py): fix linting errors
* test: skip if file not found
* style: cleanup unused import
* docs(configs.md): add docs on setting custom tokenizer
* feat(langfuse/): support langfuse prompt management
Initial working commit for langfuse prompt management support
Closes https://github.com/BerriAI/litellm/issues/6269
* test: update test
* fix(litellm_logging.py): suppress linting error
