What does this implement/fix? Explain your changes.

This fixes IBAV position issues in the SwiftUI example of the example app by adding ignorersSafeArea modifier to the body.

I also fixed a small warning in the example app while I was at it.

Does this close any currently open issues?

#1734 and a couple of others probably

Any other comments?

The fix also needs IBAV 6.3.0 to work properly, which was added to MessageKit today. Hence I send this PR today.

Also iOS 13 users are out of luck..., but it forced me to do a iOS version check which made things a bit ugly.

Where has this been tested?

iPhone and iPad simulator and iPhone Xs with iOS 16
MessageKit 4.2.0