Fix PDF generation – reset stream position (#40072)

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## Summary of the Pull Request
This is an additional fix that extends the work done in
https://github.com/microsoft/PowerToys/pull/40023

fix #39851

src/modules/previewpane/PdfPreviewHandler/PdfPreviewHandlerControl.cs

@@ -228,6 +228,8 @@ namespace Microsoft.PowerToys.PreviewHandler.Pdf
                     DestinationWidth = (uint)this.ClientSize.Width,
                 }).GetAwaiter().GetResult();
 
+                stream.Seek(0); // Reset the stream position to the beginning before reading.
+
                 imageOfPage = Image.FromStream(stream.AsStream());
             }