Update pipeline failed notification e-mail warning

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

app/views/notify/_failed_builds.html.haml

@@ -6,7 +6,7 @@
     #{'build'.pluralize(failed.size)}.
 %tr.table-warning
   %td{ style: "font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; border: 1px solid #ededed; border-bottom: 0; border-radius: 4px 4px 0 0; overflow: hidden; background-color: #fdf4f6; color: #d22852; font-size: 14px; line-height: 1.4; text-align: center; padding: 8px 16px;" }
-    Logs may contain sensitive data. Please consider before forwarding this email.
+    Failed builds
 %tr.section
   %td{ style: "font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; padding: 0 16px; border: 1px solid #ededed; border-radius: 4px; overflow: hidden; border-top: 0; border-radius: 0 0 4px 4px;" }
     %table.builds{ border: "0", cellpadding: "0", cellspacing: "0", style: "width: 100%; border-collapse: collapse;" }

changelogs/unreleased/sh-fix-pipeline-notification-email-warning.yml

+---
+title: Update pipeline failed notification e-mail warning
+merge_request: 42736
+author:
+type: fixed