Keep client data in sync when deleting items from wxOSX wxComboBox.

Correspondence between item indices and their client data was broken if any
items were deleted or the combobox was cleared entirely. Fix this by updating
the client data array whenever this happens.

Closes #14147.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71943 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/combobox_osx.cpp

@@ -131,11 +131,13 @@ unsigned int wxComboBox::GetCount() const
 
 void wxComboBox::DoDeleteOneItem(unsigned int n)
 {
+    m_datas.RemoveAt(n);
     GetComboPeer()->RemoveItem(n);
 }
 
 void wxComboBox::DoClear()
 {
+    m_datas.Clear();
     GetComboPeer()->Clear();
 }