Update infrastructure dependencies for v2026.2

[matthew-white]

Update any dependencies other than Backend and Frontend that need to be updated:

• Node in prod
  • Look at release schedule and make sure we're using an active LTS major version.
  • Update in:
    • service
    • nginx
    • secrets
• Node in dev
  • central-backend
  • central-frontend
• nginx-certbot
• Postgres
• SMTP
• Enketo
• Redis
• pyxform-http
• npm dependencies in test/ directory of central repo