Changes to Start Agent chat

the data/dashboardUrl response's property format changed from uri to no format for status 202

the data/updatedAt response's property format changed from date-time to no format for status 202

added the new optional request property attachmentIds

added subschema #1 subschema #2 to the request body anyOf list

the message request property's minLength was decreased from 1 to 0

added the optional property data/messages/items/activities to the response with the 202 status

added the optional property data/messages/items/attachments to the response with the 202 status

added the optional property data/messages/items/author to the response with the 202 status

added the optional property data/messages/items/clientMessageId to the response with the 202 status

added the optional property data/messages/items/research to the response with the 202 status

added the required property data/owner to the response with the 202 status

added the required property data/viewerIsOwner to the response with the 202 status

added the required property data/visibility to the response with the 202 status

endpoint added