Redo web lightbox, add animations and keyboard a11y (#9481)

* redo web lightbox, add animations

* add rect-avi to shell

* fix lingui msgs

src/components/Dialog/index.tsx

@@ -409,3 +409,7 @@ export function Handle({
 export function Close() {
   return null
 }
+
+export function Backdrop() {
+  return null
+}