fix: mixin disk usage dashboards to ignore node exporter pod changes

[QuentinBisson]

What this PR does / why we need it:

This PR fixes the disk read and writes dashboards to support node-exporter pod name changes when node changes often (tools like karpenter for instance, autoscaling, etc.) as this causes duplicate entries when checking metrics over 1h

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
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[chaudum]

Thanks! It makes a lot of sense to remove the pod from the aggregation.