The ornamental design for an extension for a lightswitch actuator, as shown and described.
FIG. 1 is a front and lower right perspective view of an extension for a
light switch actuator showing my new design. The broken line showing of
the switch face plate is included for the purpose of illustrating
environmental elements only and forms no part of the claimed design;
FIG. 2 is a left side elevational view an extension for a light switch
actuator showing my new design on a slightly reduced scale, the right side
elevational view thereof being a mirror image;