Add wideivne for amazon prime

Auditors: @bsclifton

Before the URLs used to be indistinguishable for amazon prime, but seems they updated and it's on its own domain now, which makes things very simple :D

Fix brave#5233

js/components/frame.js

@@ -589,6 +589,7 @@ class Frame extends ImmutableComponent {
  // https://www.nfl.com is said to be a widevine site but it actually uses Flash for me Oct 10, 2016
  const widevineSites = ['https://www.netflix.com',
  'http://bitmovin.com',
+ 'https://www.primevideo.com',
  'https://shaka-player-demo.appspot.com']
  const isForWidevineTest = process.env.NODE_ENV === 'test' && location.endsWith('/drm.html')
  if (!isForWidevineTest && (!origin || !widevineSites.includes(origin))) {