test: Add test for tycho encoder

Rename RouterEncoder to TychoEncoder

--- don't change below this line ---
ENG-4081 Took 21 minutes

src/encoding/evm/mod.rs

@@ -1,6 +1,6 @@
 pub mod approvals;
 mod models;
-mod router_encoder;
 mod strategy_encoder;
 mod swap_encoder;
+mod tycho_encoder;
 mod utils;