fix(ui5-wizard): make playground sample fully usable (#4457)

Author: niyap

packages/fiori/test/samples/Wizard.sample.html

@@ -164,7 +164,7 @@ <h3>Wizard</h3>
 			toStep3.removeAttribute("hidden");
 		});
 
-		sb.addEventListener("step-change", function () {
+		sb.addEventListener("selection-change", function () {
 			toStep4.removeAttribute("hidden");
 		});