Task: Sync Zendesk tickets to Slack thread

n8n workflow JSON:
{"meta":{"instanceId":"237600ca44303ce91fa31ee72babcdc8493f55ee2c0e8aa2b78b3b4ce6f70bd9"},"nodes":[{"id":"b220e0c7-3c34-4221-8fee-11c133a5345b","name":"Get ticket","type":"n8n-nodes-base.zendesk","position":[740,540],"parameters":{"id":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"id\"]}}","operation":"get"},"credentials":{"zendeskApi":{"id":"24","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"e58834a7-1a94-429f-a50c-2e27293c32a0","name":"IF","type":"n8n-nodes-base.if","position":[1140,540],"parameters":{"conditions":{"string":[{"value1":"={{$node[\"Determine\"].json[\"Slack Thread ID\"]}}","operation":"isNotEmpty"}]}},"typeVersion":1},{"id":"c6f82ab9-54f4-4f91-a4d9-018739c6519d","name":"Update ticket","type":"n8n-nodes-base.zendesk","notes":"Update the Zendesk ticket by adding the Jira issue key to the \"Jira Issue Key\" field.","position":[1540,640],"parameters":{"id":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"id\"]}}","operation":"update","updateFields":{"customFieldsUi":{"customFieldsValues":[{"id":7022397804317,"value":"={{$node[\"Create thread\"].json[\"ts\"]}}"}]}}},"credentials":{"zendeskApi":{"id":"24","name":"[UPDATE ME]"}},"notesInFlow":true,"typeVersion":1},{"id":"74d93ba5-d82d-4cc4-a177-bd86dbc18534","name":"On new Zendesk ticket","type":"n8n-nodes-base.webhook","position":[540,540],"webhookId":"b7845b15-0a44-4be5-b513-f4f4bb8989a6","parameters":{"path":"b7845b15-0a44-4be5-b513-f4f4bb8989a6","options":{},"httpMethod":"POST"},"typeVersion":1},{"id":"65d387cd-5c7a-4567-9a3c-9fa033f98ac9","name":"Create thread","type":"n8n-nodes-base.slack","position":[1340,640],"parameters":{"text":"={{$node[\"Get ticket\"].json[\"subject\"]}}","channel":"={{$node[\"Configure\"].parameter[\"values\"][\"string\"][0][\"value\"]}}","attachments":[],"otherOptions":{},"authentication":"oAuth2"},"credentials":{"slackOAuth2Api":{"id":"28","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"50f5aa84-70bc-4b08-a9cc-576fbed72636","name":"Create reply on existing thread","type":"n8n-nodes-base.slack","position":[1340,440],"parameters":{"text":"={{$node[\"On new Zendesk ticket\"].json[\"body\"][\"comment\"]}}","channel":"={{$node[\"Configure\"].parameter[\"values\"][\"string\"][0][\"value\"]}}","attachments":[],"otherOptions":{"thread_ts":"={{$node[\"Determine\"].json[\"Slack Thread ID\"]}}"},"authentication":"oAuth2"},"credentials":{"slackOAuth2Api":{"id":"28","name":"[UPDATE ME]"}},"typeVersion":1},{"id":"6d5e8df0-4b0b-487c-81be-93359976dd90","name":"Configure","type":"n8n-nodes-base.set","position":[540,360],"parameters":{"values":{"string":[{"name":"Slack channel","value":"#zendesk-updates"}]},"options":{"dotNotation":false}},"typeVersion":1},{"id":"934b95bb-2ffa-40a4-a2ca-02cfd646dd78","name":"Note","type":"n8n-nodes-base.stickyNote","position":[-20,360],"parameters":{"width":469.4813676974197,"height":268.2900466166276,"content":"## Sync Zendesk tickets to Slack threads\n### Setup\n1. Add your [Zendesk credential](https://docs.n8n.io/integrations/builtin/credentials/zendesk/) to the `Get ticket` and `Update ticket` nodes.\n2. Add your [Slack credential](https://docs.n8n.io/integrations/builtin/credentials/slack/) to `Create Thread` and `Create reply on existing thread` nodes.\n3. Open `Configure` node and change \"Slack channel\" value to your slack channel (like #zendesk-updates).\n4. Activate the workflow so it runs automatically each time a Zendesk ticket is created."},"typeVersion":1},{"id":"b582f7ff-7cc6-48dc-89fc-bc8bde13b06e","name":"Code","type":"n8n-nodes-base.code","notes":"if thread was created already in Slack","position":[940,540],"parameters":{"jsCode":"/* configure here =========================================================== */\n/*  Zendesk field ID which represents the \"Slack Thread ID\" field.\n*/\nconst ISSUE_KEY_FIELD_ID = 7022397804317;\n\n/* ========================================================================== */\nnew_items = [];\n\nfor (item of $items(\"Get ticket\")) {\n    \n    // instantiate a new variable for status\n    var custom_fields = item.json[\"custom_fields\"];\n    var slack_thread_id = \"\";\n    for (var i = 0; i < custom_fields.length; i++) {\n        if (custom_fields[i].id == ISSUE_KEY_FIELD_ID) {\n            slack_thread_id = custom_fields[i].value;\n            break;\n        }\n    }\n\n    // push the new item to the new_items array\n    new_items.push({\n        \"Slack Thread ID\": slack_thread_id\n    });\n}\n\nreturn new_items;"},"notesInFlow":true,"typeVersion":1}],"connections":{"IF":{"main":[[{"node":"Create reply on existing thread","type":"main","index":0}],[{"node":"Create thread","type":"main","index":0}]]},"Code":{"main":[[{"node":"IF","type":"main","index":0}]]},"Get ticket":{"main":[[{"node":"Code","type":"main","index":0}]]},"Create thread":{"main":[[{"node":"Update ticket","type":"main","index":0}]]},"On new Zendesk ticket":{"main":[[{"node":"Get ticket","type":"main","index":0}]]}}}