Check leaf hashes in the hash record validator

**Description**
Hash record validator can also check leaf hashes: if a hash record is for a path in the leaf path range, the validator can get the corresponding leaf (by path), hash it, and make sure the hash is as what's stored in the hash record. Based on the comment: https://github.com/hiero-ledger/hiero-consensus-node/pull/22215#discussion_r2663097953

**Dependencies**
https://github.com/hiero-ledger/hiero-consensus-node/pull/22215 is merged