Allow screensaver when video is paused.

Update mpvVideoPlayer.js.

Related to #141.

This is more ideal, especially in a desktop scenario where I might leave a video open after finishing it (but paused) before going to sleep.

native/mpvVideoPlayer.js

@@ -648,6 +648,7 @@
 
     pause() {
         window.api.player.pause();
+        window.api.power.setScreensaverEnabled(true);
     }
 
     // This is a retry after error
@@ -818,4 +819,4 @@
     }
 /* eslint-enable indent */
 
-window._mpvVideoPlayer = mpvVideoPlayer;
+window._mpvVideoPlayer = mpvVideoPlayer;