We need a little bit of async in core-client.

cc @ndelangen - composition was broken after remove the `importPolyfills().then` from here.

lib/core-client/src/manager/index.ts

@@ -5,5 +5,9 @@ import Provider from './provider';
 
 const { document } = global;
 
-const rootEl = document.getElementById('root');
-renderStorybookUI(rootEl, new Provider());
+// We need to wait a promise "tick" to allow all subsequent addons etc to execute
+// (alternatively, we could ensure this entry point is always loaded last)
+Promise.resolve().then(() => {
+  const rootEl = document.getElementById('root');
+  renderStorybookUI(rootEl, new Provider());
+});