Support Cast default media receiver app ID

[martinms-usc]

At this point CastProvider does not default to using the DEFAULT_MEDIA_RECEIVER_APP_ID included with the cast framework when initializing CastContext via cast.framework.CastContext.getInstance().setOptions().

It is not possible to pass this as a prop to the component since that component is both loading the SDK chrome.cast as well as initializing context with the receiverApplicationId. An undefined receiverApplicationId will error, and chrome.cast.media cannot be referenced by the parent of the component that loads it.

Suggested changes to CastProvider:

const defaultId = window.chrome.cast?.media?.DEFAULT_MEDIA_RECEIVER_APP_ID;
window.cast.framework.CastContext.getInstance().setOptions({
   receiverApplicationId: receiverApplicationId || defaultId,
   resumeSavedSession,
   autoJoinPolicy,
   language
});

documentation: https://developers.google.com/cast/docs/chrome_sender/integrate#initialization