fix: Don't attempt to serialize custom join rules
This is not supported by Ruma. The join_rule field, despite being
defined as a pure string, can have associated data to it based on the
join rule variant.
This means that custom and unknown enum variants might lose data when
reserializing.
Let's just skip the serialization of custom join rules in the RoomInfo,
the concrete value is still available in the state store, it's just not
kept at hand in the RoomInfo.
chore(ffi): The `federation-api` feature is useless.
This patch disables the `matrix-sdk/federation-api` in
`matrix-sdk-ffi` because it's no longer useful since the merge of
https://github.com/matrix-org/matrix-rust-sdk/pull/5919.
chore: Reduce the number of logs.
This patch removes some logs around the cross-process lock methods. This
is called pretty often by the cross-process lock task, which pollute the
log files.