OTTAWA — Canada is involved in international discussions about how to address the issue of foreign digital vendors not being subject to domestic sales tax, a parliamentary committee learned Thursday, as it prodded at a long-standing question of whether American companies such as Netflix Inc. are benefiting to the disadvantage of Canadian media companies. “The challenges related to the proper collection of sales tax on digital supplies by foreign-based vendors are not unique to Canada. It’s a difficult issue for all jurisdictions with a sales tax,” Sean...