Allow to recruit recently active subjects

based on !2139 (closed)

Similar to !2139 (closed), the wording here is challenging because we want to communicate a complex topic with few words.

I realized that we might want to ignore the usual soft/hard limits for recruitment because if it is urgent the message "Please contact provided subjects before adding new ones" is not really helpful. Then again, users can use cleanup. So I was not sure about that.