Revert "Do not send app level keep-alives for unauth WebSocket."

This reverts commit 54a2628797.

libsignal-service/src/main/java/org/whispersystems/signalservice/api/websocket/SignalWebSocket.kt

@@ -98,7 +98,7 @@ sealed class SignalWebSocket(
   }
 
   @Synchronized
-  open fun shouldSendKeepAlives(): Boolean {
+  fun shouldSendKeepAlives(): Boolean {
     return keepAliveTokens.isNotEmpty()
   }
 
@@ -300,11 +300,6 @@ sealed class SignalWebSocket(
         return Single.error(e)
       }
     }
-
-    @Synchronized
-    override fun shouldSendKeepAlives(): Boolean {
-      return false
-    }
   }
 
   /**