The ornamental design for a sling latch, as shown and described.
FIG. 1 is a perspective view of a sling latch showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is rear elevation view thereof;
FIG. 6 is a left side elevation thereof; and,
FIG. 7 is a right side elevation thereof.
The broken lines immediately adjacent the shade areas represent the bounds of the claimed design while other broken lines are directed to environment and are for illustrative purpose only. None of the broken lines form part of the claimed design.