The ornamental design for milk powder dispenser, as shown and described.
FIG. 1 is a top, front and left side perspective view of the milk powder dispenser, showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a rear and right side elevational view thereof;
FIG. 4 is a rear and left side elevational view thereof;
FIG. 5 is a front and left side elevational view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is an exploded front, top and left side perspective view of the milk powder dispenser of the previous FIGS., with the lid separated from the base.