Merge branch 'gdemay/fix-nonce-workload' into 'rc--2023-11-15_23-00'

fix: ensure nonce used for update request is at most 32 bytes

Follow-up on [MR-16066](https://gitlab.com/dfinity-lab/public/ic/-/merge_requests/16066) to ensure that update requests used in `workload_generator` use a nonce of at most 32 bytes. The previously used nonce was some bytes derived from pretty-printing a timestamp and a counter. The new nonce is the SHA2-256 of the previous bytes so that the result is guaranteed to be 32 bytes. 

See merge request dfinity-lab/public/ic!16167

rs/workload_generator/BUILD.bazel

@@ -7,6 +7,7 @@ DEPENDENCIES = [
     "//rs/canister_client",
     "//rs/canister_client/sender",
     "//rs/config",
+    "//rs/crypto/sha2",
     "//rs/monitoring/metrics",
     "//rs/http_endpoints/metrics",
     "//rs/test_utilities/identity",

rs/workload_generator/Cargo.toml

@@ -11,6 +11,7 @@ backoff = "0.3.0"
 ic-canister-client = { path = "../canister_client" }
 ic-canister-client-sender = { path = "../canister_client/sender" }
 ic-config = { path = "../config" }
+ic-crypto-sha2 = { path = "../crypto/sha2" }
 ic-ic00-types = { path = "../types/ic00_types" }
 ic-metrics = { path = "../monitoring/metrics" }
 ic-http-endpoints-metrics = { path = "../http_endpoints/metrics" }

rs/workload_generator/src/engine.rs

@@ -341,14 +341,15 @@ impl Engine {
         arg: Vec<u8>,
         n: usize,
     ) -> bool {
-        let nonce = plan.nonce.clone();
+        let nonce =
+            ic_crypto_sha2::Sha256::hash(&format!("inc {} {}", plan.nonce.clone(), n).into_bytes());
         let deadline = Instant::now() + agent.ingress_timeout;
         let (content, request_id) = prepare_update(
             &agent.sender,
             &plan.canister_id,
             method,
             arg,
-            format!("inc {} {}", nonce, n).into_bytes(),
+            nonce.to_vec(),
             expiry_time_from_now(),
             agent.sender_field.clone(),
         )