Fix issues with webhooks

[joshsmith]

Problem

We have some webhooks that are failing or are not processed. Here's a breakdown of things based on state.

We'll need to decide whether we address all of these now and in what priority. Some appear to be needed, most do not.

• 👍 looks good
• ❓ urgent question
• ❔ non-urgent question, probably doesn't need handled
• 🚫 needs fixed

processed

account.updated 👍
account.external_account.created 👍

unhandled

plan.created - nothing particularly interesting happens here since we've just created the plan
customer.source.created - likely does not need handled since it comes from us creating a card
customer.created - probably does not need handled
charge.succeeded - probably covered by invoice payment succeeded
invoice.created - probably does not need handled
invoice.payment_succeeded - handled right now, I believe
customer.updated - handled as much as we can now
application_fee.created - probably does not need handled
customer.subscription.created - likely does not need handled

[joshsmith]

@begedin Should we have handlers that explicitly ignore events with a reason that they were ignored? Might be nice to have it documented for why, originally, we had ignored them.

[begedin]

You're correct in thinking invoice.payment_succeeded is handled