PDF export using the headless Chrome Docker container fails when view access is restricted

Follow these steps to reproduce:

• configure PDF export to use the headless Chrome Docker container
• don't change the "XWiki URI" configuration. It's important that the URL used by the user to access XWiki be different from the URL used by the headless Chrome
• prevent unregistered users from viewing pages, regardless of the page rights
• try to export a wiki page to PDF (while being logged in)

The PDF export fails, because Chrome can't load the print preview URL.