Remove serialization tests from orchard_zsa in zebra-chain (as there're no such tests for Vanilla Orchard, tests from zebra-chain/src/transaction/tests/vectors.rs used instead - so we need to add ZSA related tests there)

Author: dmidem

zebra-chain/src/orchard_zsa.rs

@@ -3,9 +3,6 @@
 #[cfg(any(test, feature = "proptest-impl"))]
 mod arbitrary;
 
-#[cfg(test)]
-mod tests;
-
 mod burn;
 mod issuance;