The ornamental design for a vanity, as shown and described.
FIG. 1 is a front perspective view of the new design;
FIG. 2 is a front view of the vanity shown in FIG. 1;
FIG. 3 is a top view of the vanity shown in FIG. 1;
FIG. 4 is a right side view of the vanity shown in FIG. 1 (with the left side view being a mirror image thereof);
FIG. 5 is a bottom view of the vanity shown in FIG. 1; and,
FIG. 6 is a rear view of the vanity shown in FIG. 1.
The broken line showing of the handles, sink basin, faucet holes, and drainage hole is for illustrative purposes only and forms no part of the claimed design.