voiceOver focuses on wrong block when placing block

[lucyrubin]

Sometimes focus goes in the middle of the program instead of the start of the program.

Likely because of setting: collectionView.remembersLastFocusedIndexPath = true

We only want that property to be true right after placing a block, not while placing block

[lucyrubin]

helpful way to force focus: UIAccessibility.post(notification: .screenChanged, argument: self.blocksProgram)