on
Callback invoked when the banner is dismissed (e.g. via Braze bridge closeMessage). Set by integrators to run custom logic when the banner is dismissed. Invoked after the view's visibility is set to GONE and its WebView processing is paused. The view remains in the hierarchy so it can be reused if new content is loaded.
Parameters
snapshot
BannerDismissSnapshot with placement, stable key, and tracking id when known.