The ornamental design for a snapassembly, as shown and described.
FIG. 1 is a top view of a snap assembly showing my new design;
FIG. 2 is a bottom view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a perspective view thereof; and,
FIG. 8 is a top, front, left side perspective view of the snap assembly, showing my new design; the broken line showing of a flat belt is for illustrative purposes only, and forms no part of the claimed design.