Adds extra paragraph and screenshot to further validate DCGM exporter

[thomasvn]

Related Issue

• Adds clarification which was required in SUP-6416 and SUP-6491

Proposed Changes

Specifically calls out the DCGM_FI_PROF_GR_ENGINE_ACTIVE metric.

[mmurph3]

@thomasvn I think this is helpful and informative. Especially the prom query. This helped us with BAH.

[chipzoller]

LGTM. Minor suggestion.

[thomasvn]

Link checker seems to be flakey for https://cloud.google.com links right now. I will try to re-run it tomorrow.

 ## Summary

| Status        | Count |
|---------------|-------|
| 🔍 Total      | 1350  |
| ✅ Successful | 1297  |
| ⏳ Timeouts   | 0     |
| 🔀 Redirected | 0     |
| 👻 Excluded   | 47    |
| ❓ Unknown    | 0     |
| 🚫 Errors     | 3     |

## Errors per input

### Errors in install-and-configure/install/cloud-integration/gcp-out-of-cluster/README.md

* [500] [https://cloud.google.com/billing/docs/how-to/export-data-bigquery-tables#detailed-usage-cost-data-schema](https://cloud.google.com/billing/docs/how-to/export-data-bigquery-tables#detailed-usage-cost-data-schema) | Failed: Network error: Internal Server Error

### Errors in install-and-configure/advanced-configuration/gpu.md

* [500] [https://cloud.google.com/kubernetes-engine/docs/how-to/dcgm-metrics](https://cloud.google.com/kubernetes-engine/docs/how-to/dcgm-metrics) | Failed: Network error: Internal Server Error

### Errors in kubecost-cloud/kubecost-cloud-cloud-billing-integrations/kubecost-cloud-gcp-integration.md

* [500] [https://cloud.google.com/billing/docs/how-to/export-data-bigquery-tables#detailed-usage-cost-data-schema](https://cloud.google.com/billing/docs/how-to/export-data-bigquery-tables#detailed-usage-cost-data-schema) | Cached: Error (cached)

[thomasvn]

Link checker passed this time. Re-requesting reviews.