Changes to Create speech

the response property error/code became nullable for the status 400

the response property error/code became nullable for the status 401

the response property error/code became nullable for the status 402

the response property error/code became nullable for the status 403

the response property error/code became nullable for the status 500

the response property error/code became nullable for the status 502

the response property error/code became nullable for the status 504

added the non-success response with the status 404

added the non-success response with the status 408

added the non-success response with the status 410

added the non-success response with the status 413

added the non-success response with the status 415

added the non-success response with the status 429

added the non-success response with the status 503

added the non-success response with the status 529