fix: BackgroundPollWorker.kt new instance instead of null instance

app/src/main/java/org/thoughtcrime/securesms/loki/api/BackgroundPollWorker.kt

@@ -9,11 +9,11 @@ import nl.komponents.kovenant.all
 import nl.komponents.kovenant.functional.map
 import org.session.libsession.messaging.jobs.MessageReceiveJob
 import org.session.libsession.messaging.opengroups.OpenGroup
+import org.session.libsession.messaging.sending_receiving.pollers.ClosedGroupPoller
 import org.session.libsession.messaging.sending_receiving.pollers.OpenGroupPoller
 import org.session.libsession.utilities.TextSecurePreferences
 import org.session.libsignal.service.loki.api.SnodeAPI
 import org.session.libsignal.utilities.logging.Log
-import org.thoughtcrime.securesms.ApplicationContext
 import org.thoughtcrime.securesms.database.DatabaseFactory
 import java.util.concurrent.TimeUnit
 
@@ -78,7 +78,7 @@ class BackgroundPollWorker(val context: Context, params: WorkerParameters) : Wor
             promises.addAll(privateChatsPromise.get())
 
             // Closed groups
-            promises.addAll(ApplicationContext.getInstance(context).closedGroupPoller.pollOnce())
+            promises.addAll(ClosedGroupPoller().pollOnce())
 
             // Open Groups
             val openGroups = DatabaseFactory.getLokiThreadDatabase(context).getAllPublicChats().map { (_,chat)->