chore: track Packed Attestation metrics on Block Production dashboard (#7911)

**Motivation**

- to investigate any issues of packed attestations like in #7883

**Description**

- track Packed Attestation metrics on Block Production dashboard
<img width="854" alt="Screenshot 2025-06-04 at 16 15 12"
src="https://github.com/user-attachments/assets/ef086647-cae2-4f72-93e8-39f54c99451f"
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Co-authored-by: Tuyen Nguyen <twoeths@users.noreply.github.com>

Author: twoeths