sync_service now returns a ValidChainInformation instead of String

[tomaka]

This scopes the usage of finalized_serialize to lib.rs, and also unlocks the way for #1769 which will require knowing the finalized block from lib.rs.

[mergify]

Automatically approving tomaka's pull requests. This auto-approval will be removed once more maintainers are active.

[github-actions]

twiggy diff report

Difference in .wasm size before and after this pull request.

---

 Delta Bytes │ Item
─────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       -5531 ┊ <futures_util::future::future::fuse::Fuse<Fut> as core::future::future::Future>::poll::h9745692dcb2d598d
       +1046 ┊ smoldot::database::finalized_serialize::defs::SerializedChainInformationV1::new::h93500e94dddd5531
       -1013 ┊ smoldot::database::finalized_serialize::defs::SerializedChainInformationV1::new::h66e323ab5fde5b09
        -886 ┊ smoldot::database::finalized_serialize::defs::_::<impl serde::ser::Serialize for smoldot::database::finalized_serialize::defs::SerializedChainInformationV1>::serialize::h2357223329be280c
        +886 ┊ smoldot::database::finalized_serialize::defs::_::<impl serde::ser::Serialize for smoldot::database::finalized_serialize::defs::SerializedChainInformationV1>::serialize::hf5876c37c4aed08d
        -790 ┊ <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold::hf65b506a6e16dec4
        +771 ┊ <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold::hbbad3cd36f60aab6
        -729 ┊ <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold::hd1843861e834fbfc
        -716 ┊ prost::encoding::int32::merge::hc984c63894e7bd37
        +671 ┊ <core::iter::adapters::chain::Chain<A,B> as core::iter::traits::iterator::Iterator>::fold::hfa5fdf01106c3907
        +660 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h15bd969ba2634ed2
        +595 ┊ smoldot::database::finalized_serialize::defs::_::<impl serde::ser::Serialize for smoldot::database::finalized_serialize::defs::SerializedBabeEpochInformationV1>::serialize::h4105ca31a6309625
        +594 ┊ <rand_chacha::chacha::ChaCha20Rng as rand_core::SeedableRng>::from_seed::hbd962e674acfe2a7
        -585 ┊ smoldot::database::finalized_serialize::defs::_::<impl serde::ser::Serialize for smoldot::database::finalized_serialize::defs::SerializedBabeEpochInformationV1>::serialize::ha94fe461195dc2c7
        -566 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h9fc7d7ff9d966bda
        +565 ┊ prost::message::Message::merge::h94ba7ebf78932673
        +565 ┊ prost::message::Message::merge::hdf94a94e5e0d47a4
        +565 ┊ prost::message::Message::merge::hf3bd05ff9348ce4d
        -556 ┊ core::ptr::drop_in_place<smoldot::sync::all::AllSyncInner<futures_util::abortable::AbortHandle,(smoldot::libp2p::peer_id::PeerId,smoldot::network::protocol::block_announces::Role),()>>::ha01c717254880683
        -514 ┊ core::mem::drop::hea3dac943e09497f
        +387 ┊ ... and 712 more.
      -15464 ┊ Σ [732 Total Rows]