Fix importing call links with max expiration time

Co-authored-by: ayumi-signal <143036029+ayumi-signal@users.noreply.github.com>

ts/services/backups/import.ts

@@ -1179,7 +1179,7 @@ export class BackupImportStream extends Writable {
       name,
       restrictions: fromCallLinkRestrictionsProto(restrictions),
       revoked: false,
-      expiration: expirationMs?.toNumber() || null,
+      expiration: getTimestampFromLong(expirationMs) || null,
       storageNeedsSync: false,
     };