Fix scrollbar position in wxGrid and wxDataViewCtrl in wxUniv

Skip the event in wxEVT_SIZE handler in wxGrid and wxDataViewCtrl as it
was already done for wxListCtrl in 98c2eef619 (Fix scrollbar position in
wxListCtrl in wxUniv, 2021-09-05).

Closes #22145.

src/generic/datavgen.cpp

@@ -5634,7 +5634,7 @@ wxSize wxDataViewCtrl::GetSizeAvailableForScrollTarget(const wxSize& size)
     return newsize;
 }
 
-void wxDataViewCtrl::OnSize( wxSizeEvent &WXUNUSED(event) )
+void wxDataViewCtrl::OnSize(wxSizeEvent &event)
 {
     // We need to override OnSize so that our scrolled
     // window a) does call Layout() to use sizers for
@@ -5661,6 +5661,7 @@ void wxDataViewCtrl::OnSize( wxSizeEvent &WXUNUSED(event) )
     {
         m_headerArea->Refresh();
     }
+    event.Skip();
 }
 
 void wxDataViewCtrl::OnDPIChanged(wxDPIChangedEvent& event)

src/generic/grid.cpp

@@ -5746,12 +5746,13 @@ void wxGrid::RefreshBlock(int topRow, int leftCol,
     }
 }
 
-void wxGrid::OnSize(wxSizeEvent& WXUNUSED(event))
+void wxGrid::OnSize(wxSizeEvent& event)
 {
     if (m_targetWindow != this) // check whether initialisation has been done
     {
         // reposition our children windows
         CalcWindowSizes();
+        event.Skip();
     }
 }