Replace `data-confirm` modals with `GlModal` in `ee/app/views/groups/saml_group_links/_saml_group_link.html.haml`

Replace data-confirm modals in ee/app/views/groups/saml_group_links/_saml_group_link.html.haml with the implementation using GlModal. The up to date migration strategy can be found in the parent epic.