[Stripe] handle payment_intent.payment_failed

[igoychev]

Which area(s) of Podkrepi.bg are affected? (leave empty if unsure)

Donations

Describe the feature you'd like to request

When payment is initiated with payment_intent.created event and the card is not accepted by some reason in Stripe, it sends payment_intent.payment_failed event which we currently don't handle.

This results in donations staying in status waiting, however the closest correct status should be 'declined'.

Describe the solution you'd like

Check how @StripeWebhookHandler('payment_intent.canceled') is implemented and add implementation for payment_intent.payment_failed

Testing of stripe events is described here: https://github.com/podkrepi-bg/api/blob/master/TESTING.md

Describe alternatives you've considered

No response