Enable getting a proof for non-current account states

[igamigo]

Currently, the GetAccountProofs RPC method provides a way to retrieve public account data, alongside a merkle proof of the account being included in a block. Specifically, you can get the account's header representing the account's state, and an account storage header, which contains all top-level (meaning, either values or roots of maps) elements.

This proof is currently being generated exclusively for the chain tip. However, realistically, a user will not always have the latest block when executing a transaction that uses FPIs. For this, the current endpoint could be updated to return proofs for an arbitrary block (close to the chain tip), making transaction execution easier to set up on the user side.

[bobbinth]

I think the same strategy should be applied to the GetAccountDetailsRequest request. Though, maybe this should be a separate issue.