external_user_id used in downstream flows.curl --location --request PUT '/partners/members/' \
--header 'Content-Type: application/json' \
--data-raw '{
"phone_number": "string"
}'{
"phone_number": "string",
"external_user_id": "string",
"wallet_address": "0x0123456789abcdef0123456789abcdef01234567",
"id": "497f6eca-6276-4993-bfeb-53cbbbba6f08",
"created_at": "2019-08-24T14:15:22Z",
"updated_at": "2019-08-24T14:15:22Z"
}