fix(coprocessor): fhevm-listener, build.rs, fix rebuild condition

Author: rudy-6-4

coprocessor/fhevm-engine/fhevm-listener/build.rs

@@ -7,7 +7,7 @@ use semver::Version;
 use std::{env, fs, path::Path, process::Command};
 
 fn build_contracts() {
-    println!("cargo:rerun-if-changed=../../../host-contracts");
+    println!("cargo:rerun-if-changed=../../../host-contracts/contracts");
     // Step 1: Copy ../../contracts/.env.example to ../../contracts/.env
     let env_example = Path::new("../../../host-contracts/.env.example");
     let env_dest = Path::new("../../../host-contracts/.env");