Pull out app service user lookup
Pull out app service user lookup

I find this a lot simpler than nested try-catches and stuff

TribeMedia/synapse,TribeMedia/synapse,TribeMedia/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,TribeMedia/synapse