Task list link displayed even if no task generated

[Myddleware]

For example, if we click on the button "Run all active rules" and if a task is already running, a link is generated and display in information message :

In this case no task have been generated, we should display an error message and not a link with no task id in it that redirect to a 404 error. The link generated looks like this : <myddleware_url>/index.php/rule/task/view/Failed%20to%20create%20the%20task%20because%20another%20task%20is%20already%20running.%20Please%20wait%20for%20the%20end%20of%20this%20task%20or%20you%20can%20stop%20it%20manually./log