Summary:
For iPhones with small screen sizes (e.g: iPhone 5s), inside the `<WKWebView/>` component, videos will play in fullscreen mode. In this diff, I introduce a prop called `allowsInlineMediaPlayback` that when set to true, will allow videos to play inline.
**Note:** For videos to play inline, the HTML video element must also have a `playsinline` attribute on it.
Reviewed By: shergin
Differential Revision: D6379770
fbshipit-source-id: a0130720ffede6c24a90cad0c97a75b657d77017
4ca949b46e