I agree with above...AP seems to manifest itself differently with each child's personality. If your DD can fall asleep alone, you may just want to allow her to do that. Maybe still have an intimate routine before naps and bedtime (book, song, cuddle and kiss) and then just lay her down.
I may be wrong, so totally disregard the following if so, but I feel as though you may be wondering if she doesn't need you to fall asleep because she is not attached. Or, if she will not become attached if you aren't there when she falls asleep. And generally, I would say that even a very attached baby could still fall asleep independently, it is just a personality issue. But since your LO was with someone else for 7 months, who knows if she was sleep-trained or what? If she has been trained to cope with abandonment at night time, I suppose that is a different issue and one someone else may have better suggestions for!
Other adoptive parents may have much, much more insight than I, but I would imagine that the more she knows that you are there for her when she needs you, the more attached she will be (other times besides bedtimes). And so perhaps really focus on the times when you sense or she communicates that she needs you. Who knows, as your relationship grows maybe this will someday or sometimes include bedtimes as well.