"[T]he new legislation ... amends the [Pittsburgh Paid Sick Days Act (PSDA)] by expressly permitting employees to take sick time under the PSDA before it is accrued if the reason for use arises directly from COVID-19.... The July 29 Ordinance also requires employers to provide paid COVID sick time in addition to other forms of paid leave, so long as the employee provides notice to the employer of the need for COVID-19 sick time as soon as practicable."