This ensures the filter is sent to the sync endpoint properly. Originally found this shortcoming of the refactored test in my personal package repository, this commit upstreams the fix. Continuwuity just ignores incorrect sync filters, so this just exists for completeness.
This is because [matrix-nio](https://github.com/matrix-nio/matrix-nio) is pretty dead, and does not seem to like the new continuwuity version with the new default v12 rooms.
Mautrix is actively maintained and a good fit for basic testing of the client-server connection on NixOS.
The new out-of-box experience in continuwuity is such that you have to either
create a first (admin) user manually using `conduit --execute "users create
<name>"`, or using the temporary registration token that appears in the logs.
This needs to happen regardless of whether the server is open to registration
or if there is a pre-shared registration token. This commit makes it so that
the initial `alice` user is created in advance by the server itself. This
does not influence the quality of the nixos test in my opinion.
