Handle taskbar button recreation better in wxMSW.

Store the various parameters in wxTaskBarButton itself and reapply them when
the button is (re)created. This fixes problems with getting the "taskbar
button created" message twice, e.g. because Explorer was restarted, or getting
it too late, as now wxTaskBarButton can be configured both before and after
receiving this message.

Closes #16566.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78036 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/taskbarbutton.h

@@ -129,6 +129,7 @@ public:
     virtual bool AppendSeparatorInThumbBar() = 0;
     virtual wxThumbBarButton* RemoveThumbBarButton(wxThumbBarButton *button) = 0;
     virtual wxThumbBarButton* RemoveThumbBarButton(int id) = 0;
+    virtual void Realize() = 0;
 
 protected:
     wxTaskBarButton() { }