GroupsV2: Better group invite behavior

ts/components/ProgressModal.tsx

@@ -0,0 +1,35 @@
+import * as React from 'react';
+import { createPortal } from 'react-dom';
+import { ProgressDialog } from './ProgressDialog';
+import { LocalizerType } from '../types/Util';
+
+export type PropsType = {
+  readonly i18n: LocalizerType;
+};
+
+export const ProgressModal = React.memo(({ i18n }: PropsType) => {
+  const [root, setRoot] = React.useState<HTMLElement | null>(null);
+
+  // Note: We explicitly don't register for user interaction here, since this dialog
+  //   cannot be dismissed.
+
+  React.useEffect(() => {
+    const div = document.createElement('div');
+    document.body.appendChild(div);
+    setRoot(div);
+
+    return () => {
+      document.body.removeChild(div);
+      setRoot(null);
+    };
+  }, []);
+
+  return root
+    ? createPortal(
+        <div role="presentation" className="module-progress-dialog__overlay">
+          <ProgressDialog i18n={i18n} />
+        </div>,
+        root
+      )
+    : null;
+});