feat(ad-api): drop allow_while_using_route option

[isamu-takagi]

Description

Drop allow_while_using_route option. The restrictions added to clear_route make the same check as this option, so it is thought that it can be substituted with clear_route and set_route. We will reconsider whether chante_route needs an option.

Related: autowarefoundation/autoware_adapi_msgs#71

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Documentation URL: https://autowarefoundation.github.io/autoware-documentation/pr-633/
Modified URLs:

• https://autowarefoundation.github.io/autoware-documentation/pr-633/design/autoware-interfaces/ad-api/features/routing/
• https://autowarefoundation.github.io/autoware-documentation/pr-633/design/autoware-interfaces/ad-api/release/
• https://autowarefoundation.github.io/autoware-documentation/pr-633/design/autoware-interfaces/ad-api/types/autoware_adapi_v1_msgs/msg/RouteOption/