macosx: removed wrong check, which could make the video output disappear when...

macosx: removed wrong check, which could make the video output disappear when leaving fullscreen mode in rare cases (close #6856)
(cherry picked from commit 7100a8c8c8ba7364d5543c13ae70040a16aee17c)

modules/gui/macosx/MainWindow.m

@@ -2003,13 +2003,10 @@ static VLCMainWindow *_o_sharedInstance = nil;
     [o_video_view setFrame:[o_temp_view frame]];
     if( [[o_video_view subviews] count] > 0 )
         [[o_video_view window] makeFirstResponder: [[o_video_view subviews] objectAtIndex:0]];
-    if( [[o_video_view window] isVisible] )
-    {
     if( !b_nonembedded )
             [super makeKeyAndOrderFront:self]; /* our version contains a workaround */
     else
         [[o_video_view window] makeKeyAndOrderFront: self];
-    }
     [o_fullscreen_window orderOut: self];
     NSEnableScreenUpdates();