The ornamental design for a wallet, as shown and described.
FIG. 1 is a perspective front view of a wallet;
FIG. 2 is a front elevation view of the wallet;
FIG. 3 is a rear elevation view of the wallet;
FIG. 4 is a top plan view of the wallet;
FIG. 5 is a bottom plan view of the wallet; and,
FIG. 6 is a right side elevation view of the wallet, the left side elevation view being a mirror image thereof.
The stippling shown represents a contrasting color surface. The broken lines showing stitching are for the purposes of illustrating environment and form no part of the claimed design.