Avoid bogus assert after calling wxDatePickerCtrl::SetRange() in wxMSW.

If the old value didn't lie inside the new range, it was changed by the native
control internally but the value stored by wxDatePickerCtrl itself remained
unchanged, resulting in asserts later when the mismatch between them was
detected.

Closes #13189.

docs/changes.txt

@@ -158,6 +158,7 @@ wxMSW:
 - Don't send events for already selected radio popup menu items (Kinaou Hervé).
 - wxListCtrl::GetItemCount() in wxEVT_LIST_INSERT_ITEM is no longer off by 1.
 - Don't send bogus root selection events when clicking wxTreeCtrl (sbrowne).
+- Avoid bogus assert after calling wxDatePickerCtrl::SetRange().
 
 wxOSX/Cocoa: