[CI] Ensure that build failures are reported to an OTel Slack channel

[chalin]

Tasks

• https://cncfservicedesk.atlassian.net/browse/CNCFSD-2133 - @RobertKielty
• Create a channel to be used as a target for Netlify build errors:
  • Create private channel #otel-comms-approvers, private: https://cloud-native.slack.com/archives/C06EDFPQ5EH Oops, Netlify can't access private channels.
  • Create public channel #otel-comms-netlify-msgs,
    see https://cloud-native.slack.com/archives/C06G9AD6JAH
• Configure the Netlify-Slack integration to set notification for production build errors (only), see
  https://app.netlify.com/sites/opentelemetry/configuration/notifications

Context and info

• Fix JSBUILD-failure path issue #3707
• https://cloud-native.slack.com/archives/C040BF9TG9J/p1704747022261149

  #otel-comms-maintainers --> opting for #otel-comms-approvers
  private

• https://cloud-native.slack.com/archives/C040BF9TG9J/p1703260261365759
• https://docs.netlify.com/integrations/slack-app/
• Config panel: https://app.netlify.com/sites/opentelemetry/configuration/notifications

[chalin]

I don't have the required permissions, but I've escalated the request:

[austinlparker]

Opened a service desk ticket https://cncfservicedesk.atlassian.net/servicedesk/customer/portal/1/CNCFSD-2133?created=true

[chalin]

All done. We'll have to wait for a production build error to see if/how this works :). Closing for now.