🔧 fix: Catch deleteVectors Errors & Update RAG API docs

[danny-avila]

Summary

Addressed documentation updates and error handling improvements:

• Updated documentation to reflect new alternate environment variables prefixed with RAG for the RAG API, avoiding potential conflicts with existing LibreChat environment variables.
• Implemented graceful error handling in the deleteVectors function, ensuring proper error management

Checklist

• My code adheres to this project's style guidelines.
• I have performed a self-review of my own code.
• I have commented on complex areas of my code.
• I have made pertinent documentation changes.
• My changes do not introduce new warnings.
• I have written tests demonstrating that my changes are effective or that my feature works.
• Local unit tests pass with my changes.
• Any changes dependent on mine have been merged and published in downstream modules.