In https://gitlab.com/gitlab-org/gitlab/-/merge_requests/42395, we
started omitting logs from pipeline notification emails. The template
for pipeline notification emails still carries language that suggests
that the logs will appear in the pipeline notification email:

```
Logs may contain sensitive data. Please consider before forwarding this
email.
```

This commit drops this message and changes the table header to "Failed
builds".

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/251121