Some "pandemic stocks" are built to last -- and two of them look like buys today.The expression "pandemic stock" is sometimes applied to companies whose products or services captured investors' attention in the early days of Covid-19. Fintech giant PayPal Holdings (PYPL -0.80%) and streaming media specialist Roku (ROKU 4.96%) belonged to that group, soaring to new heights in 2021.As the public health crisis has eased, it's been mostly downhill for both stocks. Over the past three years, PayPal's and Roku's ...