Allow dompdf generation to work when HTTP authentication is enabled for a domain/server

Problem/Motivation

While trying to generate a pdf containing images, fonts behind a htaccess auth, the assets cannot be fetched by dompdf.
This issue happens, because we do not pass the auth data in print_pdf_dompdf_print_pdf_generate.

Proposed resolution

We should pass the authentification data by using the http_context option, which is provided by dompdf since version 1.2.1.