The ornamental design for a door latch jig, as shown and described.
FIG. 1 is a front perspective view of a door latch jig;
FIG. 2 is a front elevation view thereof; the rear elevation view being a mirror image thereof;
FIG. 3 is a left side elevation view thereof, the right side elevation view being a mirror image thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a front perspective view of the door latch jig, shown in use.
The broken lines in FIG. 6 depict environmental subject matter that forms no part of the claimed design, while the remaining broken lines shown in the FIGS. 1 through 5-depict portions of the door latch jig that form no part of the claimed design.