Changes to Create Codex Cost Per Credit

removed the pattern ^(?!^[-+.]*$)[+-]?0*(?:\d{0,10}|(?=[\d.]{1,21}0*$)\d{0,10}\.\d{0,10}0*$) from the request property cost_per_credit/anyOf[subschema #2]

the cost_per_credit response's property pattern ^(?!^[-+.]*$)[+-]?0*(?:\d{0,10}|(?=[\d.]{1,21}0*$)\d{0,10}\.\d{0,10}0*$) was removed for the status 201

endpoint added