* fix(deepseek/chat): convert content list to str
Fixes https://github.com/BerriAI/litellm/issues/6642
* test(test_deepseek_completion.py): implement base llm unit tests
increase robustness across providers
* fix(router.py): support content policy violation fallbacks with default fallbacks
* fix(opentelemetry.py): refactor to move otel imports behing flag
Fixes https://github.com/BerriAI/litellm/issues/6636
* fix(opentelemtry.py): close span on success completion
* fix(user_api_key_auth.py): allow user_role to default to none
* fix: mark flaky test
* fix(opentelemetry.py): move otelconfig.from_env to inside the init
prevent otel errors raised just by importing the litellm class
* fix(user_api_key_auth.py): fix auth error
