Only toggle the status label visibility if no animation is already pending

Fixes flickering especially when changing brightness.

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Sources/VLCStatusLabel.m

@@ -28,10 +28,11 @@
     [self setFrame:selfFrame];
 
     [self setNeedsDisplay];
-    [self _toggleVisibility:NO];
 
     if (_displayTimer)
         [_displayTimer invalidate];
+    else
+        [self _toggleVisibility:NO];
 
     _displayTimer = [NSTimer scheduledTimerWithTimeInterval:1.5
                                                      target:self