Follow-up from "Backport !7618 - Bump up tezos-rust-libs and update librustzcash to v5.0.0"

The following discussion from !7667 (merged) should be addressed:

• @dannywillems started a discussion:

  For a follow-up issue, not in the scope of this MR:

  This can be removed and tezos_rust_lib can be used instead.