failed to send subscriberPaymentFailedNotification email: 'NoneType' object has no attribute 'split'

[chrisjsimpson]

Is your feature request related to a problem? Please describe.
When card decline maps to an unresolved customer, the following email alter may be generated (note the None):

A recent subscription charge failed to be collected from Subscriber:

None

Email: None


                The failure code was: card_declined


                The failure message was: Your card was declined.


                Please note, payments are automatically retried and no action is required unless you wish to pause or stop the subscription from your admin dashboard.

failed to send subscriberPaymentFailedNotification email: 'NoneType' object has no attribute 'split'

Describe the solution you'd like

Describe alternatives you've considered

Additional context

https://subscribie.sentry.io/issues/9125143/?end=2025-01-23T17%3A00%3A59&project=4507951383314512&query=is%3Aunresolved%20issue.priority%3A%5Bhigh%2C%20medium%5D&referrer=issue-stream&sort=date&start=2025-01-23T14%3A30%3A00&stream_index=2