Use Noticed to deliver notifications on GPX import failure

Use Noticed to deliver notifications on GPX import failure

The previous code relied on `#deliver` (alias for `#deliver_now`) to
immediately deliver the email so that the trace could be deleted. To
work around this, we pass the details of the trace instead of the trace
record, which won't be available by the time the notifications are
ultimately delivered.

This means the trace is not there to be the `record`, so we are not
passing one. Since we can't get the recipient from the non-existing
record, we give the recipient explicitly to `#deliver_later`.

Additionally, the mailer method now needs to receive the recipient
directly, instead of extracting it from the trace record.