Notification on Too Large Event

### Problem Statement

In a Django project, we ran into a case where we knew there had to be an error happening, but nothing showed up in (hosted) Sentry.

After a lot of head scratching, we decided to check the "Stats & Usage" Tab in the Web UI settings. We then saw this:

It turns out we had a big Python dict in a local variable. Manually managing our event payload in that part of the code made everything work again.

### Solution Brainstorm

What wondered me is that:

- the python sdk didn't cut the payload down automatically, but that's an issue for their repo.
- that there is no notification.

Sentry has the ability to detect anomalies. I would love to get an email about errors not getting accepted due to "special" circumstances like above. In the end we flew blind for a couple of days without anyone noticing. Not necessarily what I'd expect.

### Product Area

Alerts

No file, test, or implementation entry point is named. Start by reviewing the Alerts product area and the existing behavior for events rejected because they are too large, then determine how a notification should be triggered and delivered. Done means users are notified when errors are not accepted for this reason.

Written by the indexing model from the issue text.