iOS ChromeSafariBrowserManager - Fixing unnecessary casting of rootViewController to FlutterViewController

[gunantosteven]

I've modified rootViewController using UINavigationController. So It's not relevant to cast the rootViewController with FlutterViewController. It would be good to check the object null or not.

I've tested it, and it works fine both UINavigationController and FlutterViewController.

[pichillilorenzo]

Ok, thanks!

Using the if statement this way:

...
if let flutterViewController = UIApplication.shared.delegate?.window.unsafelyUnwrapped?.rootViewController {
...

it already checks if rootViewController is null or not.
Inside the if block, the flutterViewController variable is for sure not null.