return sentinels with userid if members haven't been loaded yet,
return sentinels with userid if members haven't been loaded yet,

better than braking timeline continuation

matrix-org/matrix-js-sdk,krombel/matrix-js-sdk,krombel/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,krombel/matrix-js-sdk,matrix-org/matrix-js-sdk