[WebView] Fixes video embedded in articles not playing inline on iOS 10.

[alloy]

As discussed in Slack.

[ArtsyOpenSource]

	1 Warning
⚠️	Detected some Swift building time outliers

Time	Class	Function
203.8ms	SwiftyJSON.swift	get {}
161.8ms	WebSocket.swift	private func processRawMessage(buffer: UnsafePointer, bufferLen: Int)
91.2ms	LiveAuctionLotViewController.swift	@objc override func viewDidLoad()
80.1ms	Observable.swift	private final func nextTokenHash() -> Int
74.0ms	AuctionLotMetadataStackScrollView.swift	required init(viewModel: LiveAuctionLotViewModelType, salesPerson: LiveAuctionsSalesPersonType, sideMargin: String)
71.6ms	LiveAuctionsAdminViewController.swift	@objc override func viewDidLoad()
69.4ms	UIViewController+BlurredStatusView.swift	func ar_presentBlurredOverlayWithTitle(title: String, subtitle: String, buttonState: BlurredStatusOverlayViewCloseButtonState = default)
67.3ms	UIViewController+BlurredStatusView.swift	(closure)

Generated by 🚫 danger

[orta]

Looks good to me 👍