Rollbar context_error message is empty when order fails due to card_declined Stripe error

[rbarreca]

Describe the bug
When we get a Rollbar warning 'Order could not be completed' the context_error has been nil for all reports. It appears @placed_order.context[:error] doesn't contain all the error details. Might we need to reference @placed_order.context[:order].errors?

Steps to Reproduce

1. Turn on Rollbar in local dev
2. Simulate a card declined error https://stripe.com/docs/testing#cards-responses
3. Rollbar error has a nil context_error

Expected Result
Rollbar shows a useful context_error message like "Your card was declined."

Reference

• https://rollbar.com/LocalOrbit/Local-Orbit/items/581/
• https://rollbar.com/LocalOrbit/Local-Orbit/items/582/