"[T]he Healthy Families Act's 56-hour minimum accrual requirement is more demanding than many of the existing state and municipal paid sick leave laws.... The Act expressly states that it will not 'be construed to supersede (including preempting) any provision of any State or local law that provides greater paid sick time or leave rights.' Accordingly, employers subject to an existing paid sick leave law would be required to comply with the most pro-employee aspects of both the Healthy Families Act and the applicable state or local law."