The ornamental design for a lightingfixtureenclosure, as shown and described.
FIG. 1 shows a perspective view of a lighting fixture enclosure of the present invention.
FIG. 2 shows a front elevation view of the lighting fixture enclosure of FIG. 1, the rear elevation view being a mirror image of the front elevation view.
FIG. 3 shows a left side elevation view of the lighting fixture enclosure of FIG. 1, the right side elevation view being a mirror image of the left side elevation view; and,
FIG. 4 shows a top view of the lighting fixture enclosure of FIG. 1.
Portions of the lighting fixture enclosure not shown in the accompanying drawings form no part of the claimed design. The broken lines are for illustrative purposes only, and form no part of the claimed design.