The ornamental design for a mediacartridge, as shown and described.
FIG. 1 is a perspective view of a media cartridge according to our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a back elevation view thereof;
FIG. 4 is a top side elevation view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right side elevation view thereof;
FIG. 7 is a left side elevation view thereof;
FIG. 8 is a cross-section view thereof along section line 8-8 of FIG. 1; and,
FIG. 9 is a cross-section view thereof along section line 9-9 of FIG. 1.
The dash-dot-dash broken lines represent the bounds of the claimed design, while the dash-dash broken lines represent environment and form not part of the claimed design.