Collection view publishers should not have an effect before subscription

[RoryKelly]

Describe the bug
simply referencing the willDisplayCellPublisher will change the delegate of your collection view. This should only happen After subscription.

    var willDisplayCellPublisher: AnyPublisher<(cell: UICollectionViewCell, indexPath: IndexPath), Never> {
        let selector = #selector(UICollectionViewDelegate.collectionView(_:willDisplay:forItemAt:))
        return delegateProxy.interceptSelectorPublisher(selector)
            .map { ($0[1] as! UICollectionViewCell, $0[2] as! IndexPath) }
            .eraseToAnyPublisher()
    }