In this PR (https://github.com/consul/consul/pull/4683) a new syntax was introduced
in the component specs to check that the component was not rendering.
It seems interesting to add this syntax to the rest of the cases and thus unify the way
we check that a component is not rendering.
In this case, the duration of the budget cannot be determined, and the
application was crashing when trying to do so.
Now we're just returning `nil` as duration.
