chore: add rate-limited testnet rpc client (#24836)

Author: alexghr

spartan/terraform/deploy-rpc/environments/testnet/main.tf

@@ -72,17 +72,30 @@ locals {
     })
   }
 
+  # Consumers listed here get no per-minute cap (rate_limit_minute = 0). Consumers that need a
+  # finite cap go in rate_limited_consumers instead, since this loop hardcodes 0 for every entry.
   consumer_secret_names = [
     "testnet-rpc-consumer-client1"
   ]
 
-  consumers = {
-    for name in local.consumer_secret_names : name => {
-      username                       = name
-      gcp_secret_manager_secret_name = name
-      rate_limit_minute              = 0
+  rate_limited_consumers = {
+    "testnet-rpc-consumer-client2" = {
+      username                       = "testnet-rpc-consumer-client2"
+      gcp_secret_manager_secret_name = "testnet-rpc-consumer-client2"
+      rate_limit_minute              = 3000
     }
   }
+
+  consumers = merge(
+    {
+      for name in local.consumer_secret_names : name => {
+        username                       = name
+        gcp_secret_manager_secret_name = name
+        rate_limit_minute              = 0
+      }
+    },
+    local.rate_limited_consumers
+  )
 }
 
 module "environment" {