svx: fix assertion failure in SwFrameExample::InitAllRects_Impl()

online.git's 'make -C cypress_test check-desktop
spec=writer/a11y_dialog_spec.js' points out these can be 0 in practice,
just increase these from non-zero to avoid the assertion failure and
keep commit 281596e732 (cid#1606823
silence Overflowed constant, 2024-09-16) fixed.

Change-Id: I7a4ab6e3aa632345bb49f882d678c5d8af7a5e66
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/202247
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

svx/source/dialog/swframeexample.cxx

@@ -104,9 +104,15 @@ void SwFrameExample::InitAllRects_Impl(vcl::RenderContext& rRenderContext)
     aPage.SetSize(GetOutputSizePixel());
 
     sal_uInt32 nOutWPix = aPage.GetWidth();
+    if (!nOutWPix)
+    {
+        nOutWPix = 1;
+    }
     sal_uInt32 nOutHPix = aPage.GetHeight();
-
-    assert(nOutWPix > 0 && nOutHPix > 0);
+    if (!nOutHPix)
+    {
+        nOutHPix = 1;
+    }
 
     // PrintArea
     sal_uInt32 nLBorder;