add missing channel field to FetchMessageResposne (#44508)
add missing channel field to FetchMessageResposne (#44508)


markogresak/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,dsebastien/DefinitelyTyped,dsebastien/DefinitelyTyped,mcliment/DefinitelyTyped