I claim an ornamental design for a side panel extension for a modular storage shed, as shown and described.
FIG. 1 is a front view of a side panel extension embodying the present invention.
FIG. 2 is a right side view of the side panel extension of FIG. 1.
FIG. 3 is a perspective view of the side panel extension of FIG. 1; and,
FIG. 4 is a perspective view of a modular storage shed having the side panel extension of FIG. 1.
The present application is directed to the design illustrated in the drawings. The other features of the drawings, such as the oval-shaped opening in the door (see FIGS. 1-3), and the rest of the modular storage (see FIG. 4), are not considered part of the design sought to be patented, and have accordingly been shown in broken lines.