fix fallback error when activity_templates.yml doesn't exist (fixes #3465, BP from #2773) (cherry picked from commit 6864bf36d7df3b7acb25d6fc9a5c45de519140a9)
fix fallback error when activity_templates.yml doesn't exist (fixes #3465,
BP from #2773)
(cherry picked from commit 6864bf36d7df3b7acb25d6fc9a5c45de519140a9)

openpne/OpenPNE3,openpne/OpenPNE3,openpne/OpenPNE3,openpne/OpenPNE3