Improves daily Slack build pipeline status when new upstream tags are published

[andrew-m-leonard]

To better represent and display the daily Slack build status the following enhancements:

1. If upstream openjdk has published a new build tag then only report "Unhealthy" if:
   • Upstream tag published more than 3 days ago
   • AND there is no current build pipeline in progress
2. If a new upstream openjdk build tag has been published then highlight how long ago, and whether a build is "in progress"

See test output here: https://adoptium.slack.com/archives/C09NW3L2J/p1708101035777459

[github-actions]

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