The ornamental design for a tray, as shown and described.
FIG. 1 is a front right bottom isometric view of a tray showing our new design;
FIG. 2 is a front right top isometric view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a left side elevation view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines illustrate portions of the tray that form no part of the claimed design. The dot-dash broken lines in the drawings depict break lines. The break lines and the areas between the break lines form no part of the claimed design.