Fix EZP-22735: Make {{ path( 'ez_urlalias' ) }} polymorphic

A fix for already existing issue at JIRA: https://jira.ez.no/browse/EZP-22735

Common usecase is to generate an URL to content in Relation field value.
Unless we want to add Location(s) to Content object in the future, ContentInfo is always available (also on Content object), so to keep the complexity of this function down we could just expect ContentInfo or?