Fix line_layer performance issues in noetic branch

[matthewhannay567]

Right now when the line_layer plugin is enabled in global_costmap_params.yaml, there is a large delay between sending a waypoint and the robot reacting. The rate at which the robot replans is also slowed. This indicates that there is an issue with the line_layer plugin taking too much time somewhere in its code.

AC: line_layer no longer causes large delays.