VLCActionSheet: Fix bottomBackgroundView default height

On < iOS 11 devices the height was setted as if it was an iPhoneX

(cherry picked from commit 38f15d839eabb4d61ee38d0d48e8a6b2ee24f9ff)

Sources/VLCActionSheet/VLCActionSheet.swift

@@ -105,7 +105,7 @@ class VLCActionSheet: UIViewController {
     }()
 
     fileprivate lazy var bottomBackgroundViewHeightConstraint: NSLayoutConstraint = {
-        let bottomBackgroundViewHeightConstraint = bottomBackgroundView.heightAnchor.constraint(equalToConstant: cellHeight)
+        let bottomBackgroundViewHeightConstraint = bottomBackgroundView.heightAnchor.constraint(equalToConstant: 0)
         return bottomBackgroundViewHeightConstraint
     }()