Propagate errors from record consumer in debug exporter to the exporter

[npepinpe]

Describe the bug

Right now, if the record consumer in the debug receiver throws an exception, the exporter receives an error but it's not clear what went wrong. We should propagate a proper error so we have some idea of what happened there.

To Reproduce

Create a new DebugReceiver and pass a consumer which just throws an exception.

Expected behavior

A clear error is returned, 502 with an actual error message.