The ornamental design for a solarsidingpanel, as shown and described.
FIG. 1 is an isometric view of a solar siding panel showing the new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a left side view thereof; and,
FIG. 7 is a right side view thereof.
The solar siding panel is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.