Enable lockscreen video thumbnail by default

app/src/main/java/org/schabi/newpipe/player/helper/MediaSessionManager.java

@@ -89,7 +89,7 @@ public class MediaSessionManager {
     }
 
     /**
-     * Should be called on player destruction to prevent leakage.BitmapUtils
+     * Should be called on player destruction to prevent leakage.
      */
     public void dispose() {
         this.sessionConnector.setPlayer(null);

app/src/main/res/xml/video_audio_settings.xml

@@ -83,7 +83,7 @@
 
         <SwitchPreference
             app:iconSpaceReserved="false"
-            android:defaultValue="false"
+            android:defaultValue="true"
             android:key="@string/enable_lock_screen_video_thumbnail_key"
             android:summary="@string/enable_lock_screen_video_thumbnail_summary"
             android:title="@string/enable_lock_screen_video_thumbnail_title"/>