Changes to update knowledge group

added the non-success response with the status 503

added the new optional request property chunkOverlap

added the new optional request property chunkSize

added the non-success response with the status 409

added the optional property chunkOverlap to the response with the 200 status

added the optional property chunkSize to the response with the 200 status

added the non-success response with the status 403