In general we're doing things correctly so the realm file shouldn't
expand (unless mass deletions are made from it), but this is a nice way
to manually confirm the behaviour.
Sometimes if using realm studio with osu! running, for instance, the
realm file size can blow out of proportion. This will recover from such
cases.
Note that calling `RealmFactory.Compact` itself is not enough, as it
will fail unless all instances of the realm have been closed.
