The ornamental design for a modularconstructionunit, as shown and described.
FIG. 1 is a front perspective view of a modular construction unit;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof, the left side elevation view being a mirror image thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a front perspective view of the modular construction unit, shown in use with other modular construction units.
The broken lines showing other modular construction units in FIG. 7 depicts environmental subject matter that forms no part of the claimed design, while the remaining broken lines shown in the drawings depict portions of the modular construction unit that form no part of the claimed design.