Fix CodeHarbor export modal on exercises show

Author: MrSerth

app/views/exercises/show.html.slim

@@ -22,7 +22,7 @@ h1.d-inline-block
     li = link_to(ProgrammingGroup.model_name.human(count: :other), exercise_programming_groups_path(@exercise), class: 'dropdown-item') if policy(@exercise).programming_groups_for_exercise?
     li = link_to(t('shared.destroy'), @exercise, data: {confirm: t('shared.confirm_destroy')}, method: :delete, class: 'dropdown-item') if policy(@exercise).destroy?
     li = link_to(t('exercises.index.clone'), clone_exercise_path(@exercise), data: {confirm: t('shared.confirm_destroy')}, method: :post, class: 'dropdown-item') if policy(@exercise).clone?
-    li = link_to(t('exercises.export_codeharbor.label'), '', class: 'dropdown-item export-start', data: {'exercise-id': @exercise.id}) if policy(@exercise).export_external_confirm?
+    li = link_to(t('exercises.export_codeharbor.label'), '', class: 'dropdown-item export-start', data: {'exercise-id': @exercise.id, 'bs-toggle': 'modal', 'bs-target': '#transfer-modal'}) if policy(@exercise).export_external_confirm?
     li = link_to(t('exercises.download_proforma.label'), download_proforma_exercise_path(@exercise), class: 'dropdown-item', target: '_blank', rel: 'noopener noreferrer') if policy(@exercise).download_proforma?
 
 = row(label: 'exercise.title', value: @exercise.title)