[0.4.12][COMCTL32] Fix regression CORE-16280

A very old regression. The visible symptom for us was, that the Apply button in our
desk.cpl was always visible, even in case no user input was done in the dlg yet.

I am still a bit afraid, because this patch is quite new and
it might unhide issues otherwhere, but since it fixes a regression,
I decided to take that risk.

This patch is a backport of 0.4.13-dev-908-g
344d559

Author: JoachimHenze

dll/win32/comctl32/propsheet.c

@@ -1333,6 +1333,9 @@ static UINT GetTemplateSize(const DLGTEMPLATE* pTemplate)
   return ret;
 }
 
+#ifdef __REACTOS__
+static void PROPSHEET_UnChanged(HWND hwndDlg, HWND hwndCleanPage);
+#endif
 /******************************************************************************
  *            PROPSHEET_CreatePage
  *
@@ -1473,6 +1476,9 @@ static BOOL PROPSHEET_CreatePage(HWND hwndParent,
   if (!(psInfo->ppshheader.dwFlags & INTRNL_ANY_WIZARD))
       EnableThemeDialogTexture (hwndPage, ETDT_ENABLETAB);
 
+#ifdef __REACTOS__
+  PROPSHEET_UnChanged(hwndParent, hwndPage);
+#endif
   return TRUE;
 }