The ornamental design for a servingtray, as shown and described.
FIG. 1 is a perspective view of a serving tray of the invention being carried by a server, shown in dashed lines.
FIG. 2 is a top plan view of the serving tray of FIG. 1.
FIG. 3 is a first side view thereof.
FIG. 4 is a second side view thereof.
FIG. 5 is a first end view thereof.
FIG. 6 is a second end view thereof; and,
FIG. 7 is a bottom plan view thereof.
In FIG. 1, the broken line showing of a server is directed to environment and is for illustrative purposes only; the broken lines form no part of the claimed design.