node-red: remove dead VAULT_TOKEN reference from secrets template

Mirrors the same cleanup in the private automation-vm repo - the stored
value was already a revoked credential with no functional consumer.

stacks/platform/node-red/.env.secrets.ctmpl

@@ -15,7 +15,6 @@ SEERR_KEY={{ .Data.data.seerr_key }}
 SLACK_TOKEN={{ .Data.data.slack_token }}
 SONARR_KEY={{ .Data.data.sonarr_key }}
 TECHNITIUM_TOKEN={{ .Data.data.technitium_token }}
-VAULT_TOKEN={{ .Data.data.vault_token }}
 WAZUH_API_PASS={{ .Data.data.wazuh_api_pass }}
 WAZUH_INDEXER_AUTH={{ .Data.data.wazuh_indexer_auth }}
 {{ end }}