Changes to Get the experiment's TensorBoard instance

the phase response's property type changed from string to no type for status 200

added TensorBoardPhase to the phase response property allOf list for the response status 200

removed the Failed enum value from the phase response property for the response status 200

removed the Pending enum value from the phase response property for the response status 200

removed the Ready enum value from the phase response property for the response status 200

removed the Stopped enum value from the phase response property for the response status 200