🏷️ fix: Ensure modelLabel Field Usage for ModelSpecs/GPTPlugins

[danny-avila]

Summary

Closes #4223

• Modified OpenAIClient.js to use modelLabel as a fallback for chatGptLabel, ensuring a consistent label is always available.
• Updated buildOptions.js in the gptPlugins service to include modelLabel in the endpoint options, allowing for more accurate model identification.
• Refactored the getResponseSender function in parsers.ts to prioritize modelLabel when determining the response sender, improving the accuracy of sender identification.
• Enhanced the compactPluginsSchema in schemas.ts to include the modelLabel field and added logic to remove it when null, maintaining data consistency.

Testing

To test these changes:

1. Verify that the OpenAI client correctly uses the modelLabel as a fallback for chatGptLabel.
2. Test the gptPlugins endpoint to ensure it properly includes the modelLabel in its options.
3. Check various scenarios in the frontend to confirm that the correct model label is displayed for different endpoints and models.
4. Ensure that the schema changes do not introduce any unexpected behavior when handling plugin-related data.

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• My changes do not introduce new warnings
• I have tested my changes to ensure they work as expected