Fix #1904 (#1919)

.../admin/communication/websites/agenda/events_controller.rb

...trollers/admin/communication/websites/pages_controller.rb

...n/communication/websites/portfolio/projects_controller.rb

...trollers/admin/communication/websites/posts_controller.rb

app/controllers/admin/education/programs_controller.rb

app/controllers/admin/university/organizations_controller.rb

app/models/communication/website/agenda/event.rb

app/models/communication/website/page.rb

app/models/communication/website/portfolio/project.rb

app/models/communication/website/post.rb

app/models/concerns/shareable.rb

app/models/education/program.rb

app/models/university/organization.rb

app/views/admin/application/shared_image/_edit.html.erb

app/views/admin/application/shared_image/_static.html.erb

...admin/communication/websites/agenda/events/_form.html.erb

...dmin/communication/websites/agenda/events/static.html.erb

app/views/admin/communication/websites/pages/_form.html.erb

app/views/admin/communication/websites/pages/static.html.erb

.../communication/websites/portfolio/projects/_form.html.erb