Reduce AWS Lambda deploy splay. (#23330)

The purpose of this limit was to splay updates to avoid overloading AWS control plane API. However, adding a splay so large, started adding confusion since it takes 30 minutes between deploying backend and changes to the AWS Lambda code taking effect.

The long term correct solution is to have a global rate limiter that rate limits AWS Lambda Control Plan updates. Lower the splay as a stop gap measure.

GitOrigin-RevId: 87ddab1a12215064cd491ad521ea66c5106d54f9

crates/common/src/knobs.rs

@@ -766,7 +766,7 @@ pub static BACKEND_ISOLATE_ACTIVE_THREADS_PERCENT: LazyLock<usize> =
 /// How long to splay deploying AWS Lambdas due to changes in the backend. This
 /// know doesn't delay deploys that are required due to user backends.
 pub static AWS_LAMBDA_DEPLOY_SPLAY_SECONDS: LazyLock<Duration> =
-    LazyLock::new(|| Duration::from_secs(env_config("AWS_LAMBDA_DEPLOY_SPLAY_SECONDS", 1800)));
+    LazyLock::new(|| Duration::from_secs(env_config("AWS_LAMBDA_DEPLOY_SPLAY_SECONDS", 300)));
 
 /// The number of seconds backend should wait for requests to drain before
 /// shutting down after SIGINT.