chore(litellm): CI Failures For LiteLLM

[ialisaleh]

Closes #2563

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Note

Improves reliability of LiteLLM instrumentation and tests.

• Embedding results handling: In _finalize_span, read embedding and index from each item (dict or object), skip entries missing either, and record vectors as numeric tuples or base64 strings under EMBEDDING_EMBEDDINGS.{index}.EMBEDDING_VECTOR.
• Tests updated: test_embeddings now accepts vectors as tuple or str.
• CI stability: Added patch_tiktoken_encoding fixture to mock tiktoken.get_encoding in token count tests (avoids network calls) and adjusted imports/usages accordingly.

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