Fix wrong order of parachain blocks at initialization

[tomaka]

When we subscribe to parachain blocks, the subscription confirmation contains the list of all blocks that already exist. This list of blocks needs to be ordered from parent to child, and the field is actually named non_finalized_blocks_ancestry_order ("ancestry order") in order for everyone to get the memo.

Unfortunately, the author of the parachains code (me) didn't get the memo, and the parachain blocks aren't properly ordered.
This leads to a panic in runtime_service.rs because it assumes that the ordering is correct.

[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
─────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────
        -963 ┊ hashbrown::raw::RawTable<T,A>::reserve_rehash::hae6d9bba2cebb72a
        -373 ┊ <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h7e76bd2e9b10b361
        +285 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold::hbe97d819d80395f5
        +270 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h26d3312a567c4e2c
        -270 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::hfdacbb2b2e07eb36
        -244 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::he32ea814f6c1e49c
        +241 ┊ core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &mut F>::call_once::hf3e93dc6e60df506
        -241 ┊ core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &mut F>::call_once::hf7d80057d8cf6f1c
        +234 ┊ alloc::raw_vec::RawVec<T,A>::grow_amortized::h72e6f13d1a7f7fd5
        -233 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h32012c119fc87478
        +233 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h5e869a52455210d6
        +223 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h2c59176d86cf3e4c
        -223 ┊ <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::h425e5595a195e292
        -216 ┊ <hashbrown::raw::RawIter<T> as core::iter::traits::iterator::Iterator>::next::hc874a5afa85369ea
        +191 ┊ alloc::raw_vec::RawVec<T,A>::allocate_in::hd0c90a36a1a0765f
        -167 ┊ hashbrown::raw::RawTable<T,A>::fallible_with_capacity::h45879e1e2f1af6fc
        +163 ┊ alloc::vec::Vec<T,A>::extend_desugared::h42d44cc515debfab
        -163 ┊ alloc::vec::Vec<T,A>::extend_desugared::he3dbc3a1c5f84cba
        -160 ┊ alloc::vec::Vec<T,A>::extend_desugared::hc09e53178f377e06
        -151 ┊ <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::next::hd9f66d08ada6d19f
        +557 ┊ ... and 57 more.
       -1316 ┊ Σ [77 Total Rows]