* Companion for Trim compact solution for length during preparation

https://github.com/paritytech/substrate/pull/8317



* eliminate potential for overflow in OffchainSolutionLengthLimit

* Apply suggestions from code review

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>

* update substrate: cargo update -p sp-io

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>