Revisit code duplication between `Smt` and `LargeSmt`

There is overlap between `Smt` and `LargeSmt`. For example, `LargeSmt::build_subtrees_from_sorted_entries(...)` mirrors logic in the concurrent `Smt`.

We should revisit both implementations and reduce code duplication where possible to simplify maintenance and keep behavior consistent.

From PR 0xMiden/crypto#438 discussions [here](https://github.com/0xMiden/crypto/pull/438#discussion_r2320879897), [here](https://github.com/0xMiden/crypto/pull/438#discussion_r2320859090) and [here](https://github.com/0xMiden/crypto/pull/438#discussion_r2320834570).