(DOCS-2659) Add clusterChecksRunner:true to DBM helm setup

[jtappa]

What does this PR do?

Adds a missing step to the helm install for DBM setup, and fixes a missing >

Motivation

Additional Notes

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Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/jorie/DOCS-2659/database_monitoring/setup_postgres/aurora
• https://docs-staging.datadoghq.com/jorie/DOCS-2659/database_monitoring/setup_postgres/azure
• https://docs-staging.datadoghq.com/jorie/DOCS-2659/database_monitoring/setup_postgres/gcsql
• https://docs-staging.datadoghq.com/jorie/DOCS-2659/database_monitoring/setup_postgres/rds