The ornamental design for an activityvest, as shown and described.
FIG. 1 is a left-front perspective view of the activity vest;
FIG. 2 is a front view of the activity vest shown in FIG. 1;
FIG. 3 is a rear view of the activity vest shown in FIG. 1;
FIG. 4 is a right side view of the activity vest shown in FIG. 1;
FIG. 5 is a left side view of the activity vest shown in FIG. 1;
FIG. 6 is a top view of the activity vest shown in FIG. 1; and,
FIG. 7 is a bottom view of the activity vest shown in FIG. 1.
The subject matter shown in dashed lines, and any surfaces of the design not shown, including interior surfaces, form no part of the claimed invention.