🐛 fix: Assistants Endpoint Handling in createPayload Function

[danny-avila]

Summary

Closes #8100

I fixed the logic in the createPayload function to properly build the server URL for Assistants endpoints, ensuring endpointType is respected and that '/modify' is appended only for edited payloads. I also bumped the librechat-data-provider package version to 0.7.89 to reflect the update.

• Updated the endpoint URL construction in createPayload to use endpointType when defined and handle '/modify' path only when isEdited is true for Assistants endpoints.
• Ensured correct support for both 'assistants' and 'azureAssistants' endpoint types.
• Incremented the version of librechat-data-provider to 0.7.89 in package.json.

Change Type

• Bug fix (non-breaking change which fixes an issue)
• Documentation update

Testing

I manually tested assistant endpoint payloads with and without edits, verifying that the URLs are constructed accurately for both 'assistants' and 'azureAssistants'. I recommend running regression tests for conversations using these endpoints, and checking that modified payloads reach the /modify route only when editing is intended.

Test Configuration:

• local development
• modified and created conversations using Assistants endpoints

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
• 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

[walbercardoso]

Thank you @danny-avila