fix(FEC-10510): iOS14 - cannot exit from native PiP by the player's P…

…iP button (#483)

* Don't use `exitPictureInPicture` when it's native PiP but use `webkitSetPresentationMode('inline')`
* Remove the redundant `LEAVE_PICTURE_IN_PICTURE` firing. it's already fired natively. 

Solves FEC-10510

src/engines/html5/html5.js

@@ -533,7 +533,7 @@ export default class Html5 extends FakeEventTarget implements IEngine {
       // Currently it's supported in chrome and in safari. So if we consider checking support before,
       // we can use this flag to distinguish between the two. In the future we might need a different method.
       // Second condition is because flow does not support this API yet
-      if (document.pictureInPictureEnabled && typeof document.exitPictureInPicture === 'function') {
+      if (document.pictureInPictureEnabled && typeof document.exitPictureInPicture === 'function' && this._el === document.pictureInPictureElement) {
         document.exitPictureInPicture().catch(error => {
           this.dispatchEvent(
             new FakeEvent(
@@ -544,8 +544,6 @@ export default class Html5 extends FakeEventTarget implements IEngine {
         });
       } else if (typeof this._el.webkitSetPresentationMode === 'function') {
         this._el.webkitSetPresentationMode('inline');
-        // Safari does not fire this event but Chrome does, normalizing the behaviour
-        setTimeout(() => this.dispatchEvent(new FakeEvent(Html5EventType.LEAVE_PICTURE_IN_PICTURE)), 0);
       }
     } catch (error) {
       this.dispatchEvent(