Add validation for request schemas

[3coins]

Summary

SageMaker endpoint settings in the chat panel doesn't have any validation for the request and response schemas. This can trip users who might copy the schemas from notebooks mostly in python which might not be interoperable and decodable when passed between the JS and Python. Users currently will not realize this error until they ask a question in the chat panel.

An example of an input schema for the flan-t5-xl model that caused this error for me.

{"text_inputs":"<prompt>", "max_length":50, "num_return_sequences":3, "top_k":50, "top_p":0.95, "do_sample":True}

The last value is incorrect as it is not a valid JSON value, should be true instead of True.

Proposed Solution

Add json validation for request and response schemas in the settings panel.

[JasonWeill]

To clarify, the request schema should be validated as JSON, and the response path should be validated as JSONPath.