fix(avoidance): bug in the logic to judge whether it's a parked vehicle

[satoshi-ota]

Description

The avoidance module couldn't create avoidance path in following situation. The module makes avoidance path for object on the ego's lane only when it's a parked vehicle. And, it assumed there is no parked vehicle on ego's lane if the lane has both right and left adjacent lane.

On the other hand, if the right or left lane is a road shoulder lane, there is a possibility that there is parked vehicle on ego's lane. (if it is a large vehicle and the road should is narrow, maybe the vehicles position is on ego's lane.)

However, since previous avoidance module considered the road shoudler lanes as road lanes, the module didn't create avoidance path in following situation.

In this PR, I fixed the argument in order not to get adjacent road shoulder lanelet in following function.

    const auto right_lane =
      planner_data->route_handler->getRightLanelet(object.overhang_lanelet, true, false);
    const auto left_lane =
      planner_data->route_handler->getLeftLanelet(object.overhang_lanelet, true, false);

Additionally, this PR includes small refactoring as well (remove unused function getTargetLanelets).

Tests performed

• PASS TIER IV INTERNAL SCENARIOS

Effects on system behavior

Fix bug.

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[shmpwk]

LGTM