Update tab-complete state onRoom received after joining
Update tab-complete state onRoom received after joining

As opposed to doing it when the component mounts.

Fixes https://github.com/vector-im/riot-web/issues/3700 (hopefully)

aperezdc/matrix-react-sdk,aperezdc/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,aperezdc/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,aperezdc/matrix-react-sdk,matrix-org/matrix-react-sdk