Reduce Signal message polling frequency from 15s to 30s

apps/bridge-worker/tasks/fetch-signal-messages.ts

@@ -205,17 +205,16 @@ const fetchSignalMessagesTask = async ({
 
   if (scheduleTasks === "true") {
     // because cron only has minimum 1 minute resolution
-    for (const offset of [15000, 30000, 45000]) {
-      await worker.addJob(
-        "fetch-signal-messages",
-        { scheduleTasks: "false" },
-        {
-          maxAttempts: 1,
-          runAt: new Date(Date.now() + offset),
-          jobKey: `fetchSignalMessages-${offset}`,
-        },
-      );
-    }
+    // schedule one additional job at 30s to achieve 30-second polling
+    await worker.addJob(
+      "fetch-signal-messages",
+      { scheduleTasks: "false" },
+      {
+        maxAttempts: 1,
+        runAt: new Date(Date.now() + 30000),
+        jobKey: "fetchSignalMessages-30000",
+      },
+    );
   }
 
   const messagesClient = new MessagesApi(config);