The ornamental design for the sandal with inner ankle strap, as shown and described.
FIG. 1 is a perspective illustration of the sandal with inner ankle strap;
FIG. 2 is a right side view thereof; FIG. 3 is a left side view thereof;
FIG. 4 is a rear view thereof; FIG. 5 is a front view thereof; FIG. 6 is a
top view thereof; and, FIG. 7 is a bottom view thereof.