If a referrer hasn't been specified, use empty string
If a referrer hasn't been specified, use empty string

This is interpretted by the RTS as a non-referred team member who still needs the team token to access their welcome page etc.

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