Prepares semantics_update_test for upcoming link URL change (#151261)

Prepares for flutter/engine#53507 by adding a missing parameter to the `updateNode` test method.

Part of flutter/flutter#150263

Author: harryterkelsen

packages/flutter/test/semantics/semantics_update_test.dart

@@ -213,6 +213,7 @@ class SemanticsUpdateBuilderSpy extends Fake implements ui.SemanticsUpdateBuilde
     required Int32List childrenInHitTestOrder,
     required Int32List additionalActions,
     int headingLevel = 0,
+    String? linkUrl,
   }) {
     // Makes sure we don't send the same id twice.
     assert(!observations.containsKey(id));