Let the AppCoordinator take care of the connection requirements via
modals:
- onInteractiveLogin() - now presented on AppError
- onProviderEntityRequired()
- onPurchaseRequired()
- Any other connection error
Subviews must not use tunnel.connect(), rather they route connection
requests via the ConnectionFlow callbacks. In particular, migrate to the
AppCoordinator the connection logic from:
- TunnelToggleButton.perform()
- ProviderEntitySelector.onSelect()
onInteractiveLogin() and onPurchaseRequired() are now handled
internally, while onProviderEntityRequired() is kept public because it's
how subviews may present the entity selector.
Extras:
- Avoid modals overlap with a 500ms delay
- Shrink interactive login size on macOS
