feat(css): add CSS utility classes to the ionic theme bundle to match other themes (#29974)

The default (iOS/MD) bundle is removed from the tests for the `ionic` theme because it adds global component styles that the `ionic` theme does not need. The missing utility files are imported, and padding/margin classes are generated from the design tokens, as many tests rely on `ion-padding` and `ion-text-center` being available. This change ensures the `ionic` theme includes the same classes offered in our documentation: https://ionicframework.com/docs/layout/css-utilities.

core/scripts/testing/scripts.js

@@ -47,6 +47,11 @@
       linkTag.setAttribute('href', '/css/ionic/bundle.ionic.css');
       document.head.appendChild(linkTag);
     }
+
+    const defaultThemeLinkTag = document.querySelector('link[href*="css/ionic.bundle.css"]');
+    if (defaultThemeLinkTag) {
+      defaultThemeLinkTag.remove();
+    }
   }
 
   window.Ionic = window.Ionic || {};