don't start other pollers when app is activated in backgroud

Session/Home/HomeVC.swift

@@ -353,7 +353,7 @@ final class HomeVC: BaseVC, LibSessionRespondingViewController, UITableViewDataS
         )
         
         // Start polling if needed (i.e. if the user just created or restored their Session ID)
-        if Identity.userExists(), let appDelegate: AppDelegate = UIApplication.shared.delegate as? AppDelegate {
+        if Identity.userExists(), let appDelegate: AppDelegate = UIApplication.shared.delegate as? AppDelegate, !Singleton.appContext.isInBackground {
             SNLog("[HomeVC]: Starting pollers...")
             appDelegate.startPollersIfNeeded()
         }

Session/Notifications/PushRegistrationManager.swift

@@ -284,7 +284,8 @@ public enum PushRegistrationError: Error {
         guard
             let uuid: String = payload["uuid"] as? String,
             let caller: String = payload["caller"] as? String,
-            let timestampMs: Int64 = payload["timestamp"] as? Int64
+            let timestampMs: UInt64 = payload["timestamp"] as? UInt64,
+            TimestampUtils.isWithinOneMinute(timestampMs: timestampMs)
         else {
             SessionCallManager.reportFakeCall(info: "Missing payload data") // stringlint:ignore
             return