fix(events): only trigger task.updated once when marking task done

Resolves https://github.com/go-vikunja/vikunja/issues/1724

pkg/events/testing.go

@@ -61,3 +61,20 @@ func TestListener(t *testing.T, event Event, listener Listener) {
 	err = listener.Handle(msg)
 	require.NoError(t, err)
 }
+
+// ClearDispatchedEvents clears the list of dispatched test events. This is useful when you want to
+// test event dispatch counts in a specific section of code without events from previous test operations.
+func ClearDispatchedEvents() {
+	dispatchedTestEvents = nil
+}
+
+// CountDispatchedEvents counts how many events of a specific type have been dispatched.
+func CountDispatchedEvents(eventName string) int {
+	count := 0
+	for _, testEvent := range dispatchedTestEvents {
+		if testEvent.Name() == eventName {
+			count++
+		}
+	}
+	return count
+}