The ornamental design for a handset, as shown and described.
FIG. 1 is a front perspective view of a handset showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a top view thereof; and,
FIG. 6 is a bottom view thereof.
The broken lines and the unshaded regions bounded by broken lines form no part of the claimed design.