We claim the ornamental design for a mirror bracket, as shown and described.
FIG. 1 is a perspective view of the design of the present invention for a mirror bracket, the broken lines are showing a mirror and attachment knob for illustrative purposes only and form no part of the claimed design.
FIG. 2 is a front elevation view of the invention of FIG. 1;
FIG. 3 is a rear elevation view of the invention of FIG. 1;
FIG. 4 is a left side elevation view of the invention of FIG. 1;
FIG. 5 is a right side elevation view of the invention of FIG. 1;
FIG. 6 is a top view of the invention of FIG. 1; and,
FIG. 7 is a bottom view of the invention of FIG. 1.