bug(http): fix task duration

meilisearch-http/src/task.rs

@@ -224,13 +224,13 @@ impl From<Task> for TaskView {
             _ => unreachable!("A task must always have a creation event."),
         };
 
-        let duration = finished_at.map(|ts| (ts - enqueued_at));
-
         let started_at = events.iter().find_map(|e| match e {
             TaskEvent::Processing(ts) => Some(*ts),
             _ => None,
         });
 
+        let duration = finished_at.zip(started_at).map(|(tf, ts)| (tf - ts));
+
         Self {
             uid: id,
             index_uid: index_uid.into_inner(),