Flakiness/#of Attempts report in dashboard - upgrade

[alexniculae]

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What is this feature about (1 sentence)

• Add count of the Retries, on the run card, in the list of runs.
• Always display the Retries icon, even if the count is 0 (like we do for the skips)
  • both on the run card inside the run and
  • on the run card in the list of runs
• Include the Retires stats in the Slack integration report message

Why is it needed? What is the value? For whom do we build it?

This would make it more clear and safe to ensure there are no Retries on a run

High-level feature overview

As discussed in #326