The ornamental design for a pacifiertether, as shown and described.
FIG. 1 is a perspective view of a pacifier tether, showing the new design broken away;
FIG. 2 is a top plan view showing the new design;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is an end view thereof; and,
FIG. 6 is an opposite end view thereof.
The broken lines depicting a clip represent environmental subject matter that forms no part of the claimed design. All other broken lines depict portions of the article that form no part of the claimed design.