docs: Canary Grafana Dashboard Panel for workflow success counter (#7464)

<!-- Describe what has changed in this PR -->
**What changed?**
Added Panel for dashboard workflow success counter to show canary
metrics

<!-- Tell your future self why have you made these changes -->
**Why?**
Was missing

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test? Checked in staging env? -->
**How did you test it?**
Locally 
<img width="724" height="312" alt="Screenshot 2025-11-19 at 3 45 13 PM"
src="https://github.com/user-attachments/assets/289d501c-f6b7-412f-91a4-595bed62922d"
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Signed-off-by: [email protected] <[email protected]>

Author: vishwa-uber