macosx: fix race condition which caused hiding the main split view (close #11103)

modules/gui/macosx/VLCVoutWindowController.m

@@ -196,6 +196,7 @@
     [o_new_video_window setHasActiveVideo: YES];
     [o_vout_dict setObject:[o_new_video_window autorelease] forKey:[NSValue valueWithPointer:p_wnd]];
 
+    [[VLCMain sharedInstance] setActiveVideoPlayback: YES];
     [[VLCMainWindow sharedInstance] setNonembedded:!b_mainwindow_has_video];
 
     // beware of order, setActiveVideoPlayback:, setHasActiveVideo: and setNonembedded: must be called before

modules/gui/macosx/intf.m

@@ -135,8 +135,6 @@ int WindowOpen(vout_window_t *p_wnd, const vout_window_cfg_t *cfg)
         return VLC_EGENERIC;
     }
 
-    [[VLCMain sharedInstance] setActiveVideoPlayback: YES];
-
     SEL sel = @selector(setupVoutForWindow:withProposedVideoViewPosition:);
     NSInvocation *inv = [NSInvocation invocationWithMethodSignature:[o_vout_controller methodSignatureForSelector:sel]];
     [inv setTarget:o_vout_controller];