Changes to Preview user-assigned battle sides

the request property sides became not nullable

the request property sides/items/entities became not nullable

added the optional property battle_id to the response with the 200 status

added the optional property killmail_id to the response with the 200 status

added the optional property unsided to the response with the 200 status

added the required property alliances_involved to the response with the 200 status

added the required property characters_involved to the response with the 200 status

added the required property corporations_involved to the response with the 200 status

added the required property duration_minutes to the response with the 200 status

added the required property end_time to the response with the 200 status

added the required property is_custom to the response with the 200 status

added the required property is_multi_party to the response with the 200 status

added the required property kill_count to the response with the 200 status

added the required property region_id to the response with the 200 status

added the required property region_name to the response with the 200 status

added the required property solar_system_id to the response with the 200 status

added the required property solar_system_name to the response with the 200 status

added the required property solar_system_security to the response with the 200 status

added the required property start_time to the response with the 200 status

added the required property team_entities to the response with the 200 status

added the required property teams to the response with the 200 status

added the required property total_damage to the response with the 200 status

added the required property total_isk_destroyed to the response with the 200 status

added required request body