Base58-encoding signature consisting of all zero bytes produces edsig encoding, which doesn't match reference

[lierdakil]

Describe the bug

Base58-encoding signature consisting of all zero bytes produces edsig encoding, which doesn't match Octez implementation:

$ octez-client --mode mockup --protocol PtN normalize data 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 of type signature --unparsing-mode Readable
...
"sigMzJ4GVAvXEd2RjsKGfG2H9QvqTSKCZsuB2KiHbZRGFz72XgF6KaKADznh674fQgBatxw3xdHqTtMHUZAGRprxy64wg1aq"

but tezos_crypto_rs::hash::Signature([0; 64].to_vec()).to_b58check() produces "edsigtXomBKi5CTRf5cjATJWSyaRvhfYNHqSUGrn4SdbYRcGwQrUGjzEfQDTuqHhuA8b2d8NarZjz8TRf65WkpQmo423BtomS8Q"

Note, however, that base58-encoded ed25519 signature survives the round-trip:

$ octez-client --mode mockup --protocol PtN normalize data '"edsigtXomBKi5CTRf5cjATJWSyaRvhfYNHqSUGrn4SdbYRcGwQrUGjzEfQDTuqHhuA8b2d8NarZjz8TRf65WkpQmo423BtomS8Q"' of type signature --unparsing-mode Readable
"edsigtXomBKi5CTRf5cjATJWSyaRvhfYNHqSUGrn4SdbYRcGwQrUGjzEfQDTuqHhuA8b2d8NarZjz8TRf65WkpQmo423BtomS8Q"

To Reproduce

    #[test]
    fn test() {
        assert_eq!(
            &tezos_crypto_rs::hash::Signature([0; 64].to_vec()).to_b58check(),
            "sigMzJ4GVAvXEd2RjsKGfG2H9QvqTSKCZsuB2KiHbZRGFz72XgF6KaKADznh674fQgBatxw3xdHqTtMHUZAGRprxy64wg1aq"
        );
    }

Expected behavior

Test passes.