The ornamental design for a chandelier, as shown and described.
FIG. 1 is a front view of a chandelier showing my design. The side views and back view are identical to the front view and, therefore, have been omitted.
FIG. 2 is a top view thereof; and,
FIG. 3 is a bottom view thereof.
The broken line showing of the glass holders and shades is for illustrative purposes only and forms no part of the claimed design.