Fetches the game's product catalog.
It makes an async call to the API, so the result isn't available immediately.
If they are successfully subscribed this plugin will emit the getcatalog
event along
with the catalog data.
If they cannot, i.e. it's not in the list of supported APIs, or the request
was rejected, it will emit a getcatalogfail
event instead.
This Facebook Instant Games Plugin instance.