[FIX] website_event_track: listen for pwa install event earlier

To display the PWA's install banner, the browser triggers a
`beforeinstallprompt` event when he estimates that all the requirements
for installation are fulfilled (e.g. Service-worker, manifest...).

But we have observed that the browser can trigger this event really
early in the loading of the page and even before our listener has been
registered, failing to display the banner.

This commit moves the event listener's registration out of the lifecycle
of our widget to allow it to be registered as soon as possible,
drastically reducing the risk of missed-events.

0 files changed, 0 insertions, 0 deletions