The ornamental design for a foot pedal, as shown and described.
FIG. 1 is a top isometric view of a foot pedal in accordance with the new design;
FIG. 2 is a front right side isometric view thereof;
FIG. 3 is a right side elevation view thereof, a left side elevation view being a mirror image thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken line showing in FIG. 6 represents the bounds of the claimed design, with the lines themselves and the areas within them forming no part of the claimed design.