Buttons: Refactor & use new theme (#32767)

* WIP button styles refactoring

* Starting to work

* Tweak form disabled color

* Emotion performance tests

* More benchmarks

* added classnames prop

* Button class names refactor test

* revert to old style generation

* Wrapping up

* Updates

* Updated tests

public/app/routes/routes.tsx

@@ -441,6 +441,12 @@ export function getAppRoutes(): RouteDescriptor[] {
         () => import(/* webpackChunkName: "PlaylistEditPage"*/ 'app/features/playlist/PlaylistEditPage')
       ),
     },
+    {
+      path: '/sandbox/benchmarks',
+      component: SafeDynamicImport(
+        () => import(/* webpackChunkName: "BenchmarksPage"*/ 'app/features/sandbox/BenchmarksPage')
+      ),
+    },
     ...extraRoutes,
     {
       path: '/*',