fix: litellm conflict with openai on lib override

[teocns]

Fixes #471

• Removed original_oai_create and original_oai_create_async variables since we no longer override OpenAI's methods
• Modified override() and undo_override() to only handle LiteLLM's methods
• Updated _override_completion() and _override_async_completion() to only store and patch LiteLLM's methods

This way, when both providers are used:

• OpenAIProvider will handle overriding OpenAI's completion methods
• LiteLLMProvider will only handle overriding LiteLLM's completion methods
• No more conflicts between the two providers ✅

A bit more of explanation

LiteLLM's completion method is completely separate from OpenAI's Completions.create
Even though LiteLLM uses OpenAI's format internally, it has its own implementation
When we call litellm.completion(), it doesn't actually call OpenAI's Completions.create

Tests

Breakdown

• test_provider_override_independence():
  1. Verifies that each provider only overrides its own methods
  2. Checks that the original methods are properly stored and restored
  3. Ensures no cross-contamination between providers
• test_provider_override_order_independence():
  1. Verifies that the order of provider initialization doesn't matter
  2. Tests both possible orders (OpenAI first vs LiteLLM first)
  3. Ensures each provider's overrides remain intact regardless of order

What's being verified

• Each provider only overrides its intended methods
• Original methods are properly stored and can be restored
• The order of provider initialization doesn't affect the overrides
• No provider interferes with another provider's overrides

python tests/test_providers.py

[areibman]

I ran this in python and it didn't work for OpenAI

import litellm
import openai
import agentops

agentops.init(default_tags=["litellm"])

message = [{"role": "user", "content": "Write a 12 word poem about secret agents."}]

litellm.completion(model="claude-3-sonnet-20240229", messages=message, temperature=0)

client = openai.OpenAI()

client.chat.completions.create(model="gpt-4o", messages=message, temperature=0)```

[areibman]

@the-praxs Can you give it a look?

[the-praxs]

@the-praxs Can you give it a look?

Testing it - same issue as yesterday - only the first create uses the patched function.

I am trying to troubleshoot the root cause.

[teocns]

closing in favor of #476

[areibman]

If we want to avoid client conflicts, perhaps we can instead use their official observability documentation https://docs.litellm.ai/docs/observability/arize_integration

[teocns]

Since the other PR was closed by the author will consider this as "Resolves #471 "