[atlas] more than 10 concurrent measurements to the same target

Hi! When scheduling checks I often get the error: "We do not allow more than 10 concurrent measurements to the same target." Imo this is not correct. Yes, I do schedule more then 10 measurements to the same target, but they are not concurrent. They are sequential - one ofter the other. Thus, it would be great if this check could be fixed to consider start and stop times. Thanks Klaus