Partial revert: fix VideoDetailFragment flickering

This partially reverts commit 92a07a3445, which was needed to fix ghost notifications. There I broke the "cycle" causing the useless notifications to popup in 2 different places (see points 3 and 4 of the commit description).
However, breaking the cycle in point 4 ("`PlayerHolder::tryBindIfNeeded()` is now used to passively try to bind, instead of `PlayerHolder::startService()`" was not correct, for the following reason.
I assumed that `ACTION_PLAYER_STARTED` was used for notifying that the player was instantiated anew, while it actually is used to notify that something is now ready for use: it could be the player, but it could also just be that the bottom sheet view was just added and thus the VideoDetailFragment needs to start the player.
Therefore, when handling `ACTION_PLAYER_STARTED` it is correct to start the player service and not just try to bind to it.
The other point in which I broke the cycle (point 3) should still prevent ghost notifications, although I could not test.

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.java

@@ -1424,8 +1424,10 @@ public final class VideoDetailFragment
                             bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                         }
                         // Rebound to the service if it was closed via notification or mini player
-                        playerHolder.setListener(VideoDetailFragment.this);
-                        playerHolder.tryBindIfNeeded(context);
+                        if (!playerHolder.isBound()) {
+                            playerHolder.startService(
+                                    false, VideoDetailFragment.this);
+                        }
                         break;
                 }
             }