Feat/braze event listener

[cnguyen812]

Add event listener for Braze content card updates. Instead of just fetching content cards directly, we request a refresh and on refresh event, then we fetch content cards.

• on init, subscribe a listener and persist the subscription to listen for updates, and fetch cards on update event
• on init, since it takes a bit of time for content cards to update, we poll a few times at 5 second intervals for initial content cards
• request refresh on HomeRoot focus, throttled to every 10 seconds
• update Braze language on language change

[cmgustavo]

LGTM