The success of a project is based on the percentage when the campaign ends.
If any supporter pledges are declined, this will only affect the amount of funds transferred to you as part of your payout, it wouldn't impact your Green Light status.
The only time your Green Light status would potentially be impacted by declined charges is if you pledged to your own campaign to reach the Green Light, your own pledges were declined (causing you to have raised less than 80% of your overall goal), and you intentionally didn't make a good-faith effort to fix those declines.