fix(grafana): use drop metric for destination pod panel

[SumiReCord]

Description

Fix the Grafana panel query for "Dropped pps per Destination pod".
The panel title indicates dropped packets, but the query was using networkobservability_adv_forward_count.

Related Issue

N/A

Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• I have correctly attributed the author(s) of the code.
• I have tested the changes locally.
• I have followed the project's style guidelines.
• I have updated the documentation, if necessary.
• I have added tests, if applicable.

Screenshots (if applicable) or Testing Completed

I don't have a live Grafana environment to capture screenshots.
However, I have verified the fix logically:

• Observed issue: The panel titled "Dropped pps" was using networkobservability_adv_forward_count, which measures forwarded (successful) traffic.
• Fix: Changed the metric to the correct one for dropped packets.
• The change is a straightforward query update based on the metric definitions.

Additional Notes

N/A

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