Return fully qualified user_id as per spec
Return fully qualified user_id as per spec

TribeMedia/synapse,matrix-org/synapse,iot-factory/synapse,matrix-org/synapse,iot-factory/synapse,TribeMedia/synapse,TribeMedia/synapse,iot-factory/synapse,matrix-org/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,iot-factory/synapse,matrix-org/synapse,TribeMedia/synapse,iot-factory/synapse