fix(participant exports): fix participants by returning the export type as well as the file path

We previously used the Apollo context but that's really unreliable.

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/graphql/event.ts

@@ -482,6 +482,9 @@ export const EXPORT_EVENT_PARTICIPATIONS = gql`
     $format: ExportFormatEnum
     $roles: [ParticipantRoleEnum]
   ) {
-    exportEventParticipants(eventId: $eventId, format: $format, roles: $roles)
+    exportEventParticipants(eventId: $eventId, format: $format, roles: $roles) {
+      path
+      format
+    }
   }
 `;