Consider introducing `AccountIdKey`

[PhilippGackstatter]

After #2442 we have equivalent miden_protocol::block::account_tree::account_id_to_smt_key and TransactionAdviceInputs::account_id_map_key implementations. Maybe we should improve this with a dedicated type, for example:

/// The account ID as the key in the [`AccountTree`] and advice map in [`TransactionAdviceInputs`].
pub struct AccountIdKey(AccountId);

impl AccountIdKey {
    // Returns `[0, 0, account_id_suffix, account_id_prefix]`.
    pub fn as_word(&self) -> Word { ... }

    // Converts `[0, 0, account_id_suffix, account_id_prefix]` to Self.
    pub fn from_word(word: Word) -> Result<Self, todo!()> { ... }

    pub fn to_leaf_index(&self) -> LeafIndex<{ AccountTree::DEPTH }> { ... }
}

impl From<AccountId> for AccountIdKey { ... }

And then we can remove:

• TransactionAdviceInputs::account_id_map_key
• miden_protocol::block::account_tree::{account_id_to_smt_key, smt_key_to_account_id, account_id_to_smt_index}

[swaploard]

@bobbinth, I can take this issue.

[Himess]

Can i take it @PhilippGackstatter ?

[PhilippGackstatter]

Closed by #2495.