Deprecate delivery legacy modes fields

Support for legacy mode profiles in shipping has been discontinued. This feature has been disabled for a while, and the the GraphQL Admin API is being updated to reflect this.

The following fields are being marked as deprecated:

• DeliveryProfile.legacyMode

The following fields are effectively deprecated, as they are no longer functional:

• DeliverySetting.legacyModeBlocked
• DeliverySetting.legacyModeProfiles
• DeliverySettingInput.legacyModeProfiles

Note: These three fields can't be marked as deprecated because that would leave their objects with zero public fields, which is known to cause problems for schema generation.

The corresponding queries that use these fields now return static data that users should ignore. Any mutations that pass these fields are now be no-ops.