The ornamental design for a productdisplay, as shown and described.
FIG. 1 is a perspective view of the product display showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a left side view thereof; and,
FIG. 4 is a back view thereof.
The broken line showing of portions of the product display is included for the purpose of illustrating environmental structure and forms no part of the claimed design.