The ornamental design for a sandalsole, as shown and described.
FIG. 1 is a bottom plan view of a sandal sole showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a rear elevation view thereof; and,
FIG. 7 is a bottom, front, right side perspective view thereof.
The broken lines in the drawings showing the top surface details of the sandal sole illustrate environmental structures that form no part of the claim.