I claim the ornamental design for a manicure art applicator, as shown and described.
FIG. 1 is a front view of a manicure art applicator; and
FIG. 2 is a back view of a manicure art applicator; and
FIG. 3 is a left side view of a manicure art applicator; and
FIG. 4 is a right side view of a manicure art applicator; and
FIG. 5 is a top view of a manicure art applicator; and
FIG. 6 is a bottom view of a manicure art applicator; and,
FIG. 7 is a front view of a manicure art applicator being used for its common purpose. The broken lines in the drawing depict environmental subject matter only and form no part of the claimed design.