The ornamental design for a mobilityaidtip, as shown and described.
FIG. 1 is a top perspective view of a mobility aid tip;
FIG. 2 is a bottom perspective view;
FIG. 3 is a first side view;
FIG. 4 is a second side view;
FIG. 5 is a third side view;
FIG. 6 is a fourth side view;
FIG. 7 is a top view; and,
FIG. 8 is a bottom view.
The dashed lines depict portions of the mobility aid tip that form no part of the claimed design. The dash dot dot lines depict boundary lines of the mobility aid tip that form no part of the claimed design.