Changes to List available models

the models/items/provider response's property type changed from string to no type for status 200

added LlmProvider to the models/items/provider response property allOf list for the response status 200

removed the ANTHROPIC enum value from the models/items/provider response property for the response status 200

removed the GOOGLE enum value from the models/items/provider response property for the response status 200

removed the OPENAI enum value from the models/items/provider response property for the response status 200

removed the UNKNOWN enum value from the models/items/provider response property for the response status 200

added the optional property auth_url to the response with the 401 status

added the optional property auth_url to the response with the 500 status

added the optional property provider to the response with the 401 status

added the optional property provider to the response with the 500 status