refactor(avoidance): parameterize magic number (autowarefoundation#426)

Signed-off-by: satoshi-ota <[email protected]>

Author: satoshi-ota

autoware_launch/config/planning/scenario_planning/lane_driving/behavior_planning/behavior_path_planner/avoidance/avoidance.param.yaml

@@ -138,6 +138,7 @@
         lateral:
           lateral_execution_threshold: 0.09             # [m]
           lateral_small_shift_threshold: 0.101          # [m]
+          lateral_avoid_check_threshold: 0.1            # [m]
           road_shoulder_safety_margin: 0.3              # [m]
           max_right_shift_length: 5.0
           max_left_shift_length: 5.0