fix Stripe subscriptions deploy mode

[adnjoo]

• click subscribe -> error

TODO

• [x] check logs
  • [x] add S_S_K
  • [x] try access credentials in cloned repo
  • [x] credentials.ymc.enc, 353b98d
• [x] check logs
  • [x] add webhook_signing_secret to prod credentials
• [x] add stripe webhooks endpoint in dashboard

Screenshots

Manual test

• user checks out, success page, You're in! Subscribed..