Merge 8310b16895fd36d1e0e58b7fdb9aa34fea064e5b into 417d2ce971c85f708fb255bd2773aba12afd19f5

The unauthenticated (sealed sender) socket had no keep-alive token
registered, causing SignalWebSocket's DelayedDisconnectThread to tear
down the connection ~10s after each send. Every subsequent group message
then had to re-establish a fresh TLS connection (~6s delay).

The authenticated socket avoids this by registering a "receive" keep-alive
token for the lifetime of the receive loop. Apply the same pattern to the
unauthenticated socket: register the token alongside the authenticated one
and remove it in the same finally block.

This keeps the unidentified connection alive in daemon mode, matching the
behaviour of Signal mobile clients.

lib/src/main/java/org/asamk/signal/manager/helper/ReceiveHelper.java

@@ -102,6 +102,9 @@ public class ReceiveHelper {
         signalWebSocket.connect();
         signalWebSocket.registerKeepAliveToken("receive");
 
+        final var unauthenticatedSignalWebSocket = dependencies.getUnauthenticatedSignalWebSocket();
+        unauthenticatedSignalWebSocket.registerKeepAliveToken("receive");
+
         try {
             receiveMessagesInternal(signalWebSocket, timeout, maxMessages, handler, queuedActions);
         } finally {
@@ -110,6 +113,7 @@ public class ReceiveHelper {
             queuedActions.clear();
             signalWebSocket.removeKeepAliveToken("receive");
             signalWebSocket.disconnect();
+            unauthenticatedSignalWebSocket.removeKeepAliveToken("receive");
             webSocketStateDisposable.dispose();
             shouldStop = false;
         }