The ornamental design for a sensoryactivitysack, as shown and described.
FIG. 1 is a perspective view of the sensory activity sack;
FIG. 2 is a front view of the sensory activity sack;
FIG. 3 is a back view of the sensory activity sack;
FIG. 4 is a right side view of the sensory activity sack;
FIG. 5 is a left side view of the sensory activity sack;
FIG. 6 is a top view of the sensory activity sack; and,
FIG. 7 is a bottom view of the sensory activity sack.
The broken line are included for the purpose of illustrating unclaimed portions of the sensory activity sack as well as unclaimed environmental structure. The broken lines in the drawings form no part of the claimed design.