feat(lane_change): use external velocity limit in safety check

[zulfaqar-azmi-t4]

Description

• Lane change doesn't subscribe to external velocity limiter.
• Therefore despite planning path with maximum velocity from common param[1][2], if user changes the maximum velocity via external velocity limiter, there will be mismatch between the path point's velocity, and the current limited velocity.
• Up until this point, when performing safety check, the path point's velocity is used to perform safety check.
• This only happens in lane change module because it is the module that supports accelerating path at the moment.
• However, because of the velocity mismatch, if the limited velocity is smaller than the path point's velocity, it might cause incorrect safety check results.

To avoid this mismatch, this PR aims to use the limited velocity only during the safety check.

⚠️⚠️⚠️ Additional note

We cannot use the external velocity limiter's limited velocity during path planning in the behavior path planner. This is because the velocity planning that takes the limited velocity into consideration is performed by the motion velocity smoother, a module that executes after both the behavior path and behavior velocity are completed. If the user applies the limited velocity in an earlier module, it might cause unexpected jerk and acceleration. Therefore, do not use this information to insert velocity during path planning. This issue might be resolved in the future.

Related links

Tests performed

TIER IV internal link

Notes for reviewers

None

Interface changes

None

Effects on system behavior

We cannot use the external velocity limiter's limited velocity during path planning in the behavior path planner. This is because the velocity planning that takes the limited velocity into consideration is performed by the motion velocity smoother, a module that executes after both the behavior path and behavior velocity are completed. If the user applies the limited velocity in an earlier module, it might cause unexpected jerk and acceleration. Therefore, do not use this information to insert velocity during path planning. This issue might be resolved in the future.

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[rej55]

LGTM