Fix deep links now working as expected on cold start of the app.

[timonus]

This change works around an issue causing deep links to not work during app sessions that were started via deep link (more details here). I found that isCollapsed returns false for the entire duration of these sessions despite viewControllers only containing a single view controller, which could be considered as "collapsed". Perhaps on devices where only one view controller could ever be presented UIKit doesn't update the value if isCollapsed.

I tested this out on iPad, where isCollapsed is always false, and on an iPhone XS Max where isCollapsed can actually mutate between landscape and portrait, and everything seemed to work smoothly. I'd suggest this as a fix for the issue! If you'd like me to dig deeper on the subject I can try to find out more about the nature of this issue.

[rnystrom]

Thank you!!