Fix backup archive file's extension

bubble-server/src/main/java/bubble/resources/cloud/NetworkActionsResource.java

@@ -189,7 +189,7 @@ public class NetworkActionsResource {
         if (backup == null) throw notFoundEx(backupId);
 
         final var backupArchive = restoreService.buildRestorePackage(thisNetworkUuid, backup, passphrase);
-        final var outFileName = network.getNickname() + "." + backupId + (empty(passphrase) ? ".zip" : "");
+        final var outFileName = network.getNickname() + "." + backupId + ".tgz.enc";
 
         return send(new FileSendableResource(backupArchive).setContentType(APPLICATION_OCTET_STREAM)
                                                            .setContentLength(backupArchive.length())