Reconnect websockets after app switch

[esune]

When going through the same-device access experience, the browser is sent to background for the time necessary to the user to interact with BC Wallet. This seems to cause websockets (and potentially polling) to be terminated.

Using the focus browser window event we may be able to reconnect the client so that the UI can refresh - see https://developer.mozilla.org/en-US/docs/Web/API/Window/focus_event

[loneil]

Have tested this out in Dev environment after these changes on Clecio's iPhone while watching browser logs. Was working for shared and declined proofs successfully on BCNGN and cell network. So tentatively declaring this one cleared.