[try-runtime-cli] Improve header info retrieval

[emostov]

• Remove --header-at option by
  • for State::Snap use block hash from system pallet instead of flag with hash
    • first get block number from

      substrate/frame/system/src/lib.rs

      Line 569 in 050e4ac

      pub(super) type Number<T: Config> = StorageValue<_, T::BlockNumber, ValueQuery>;

    • then get block hash from

      substrate/frame/system/src/lib.rs

      Line 557 in 050e4ac

      pub type BlockHash<T: Config> =

  • for State::Live can simply use hash from --block-at
• For State::Snap try and allow the user to either feed in a file with the header or find a way to extract the neccesary header info from state (system pallet). This may involve extracting info and then recreating a close-enough mock header

follow up to #8966

[stale]

Hey, is anyone still working on this? Due to the inactivity this issue has been automatically marked as stale. It will be closed if no further activity occurs. Thank you for your contributions.