chore: Make a drawer on a testing page expandable (#3538)

Author: georgylobko

pages/app-layout/runtime-drawers-with-only-global.page.tsx

@@ -16,6 +16,7 @@ awsuiPlugins.appLayout.registerDrawer({
   resizable: true,
   defaultSize: 350,
   preserveInactiveContent: true,
+  isExpandable: true,
 
   ariaLabels: {
     closeButton: 'Close button',