docs: corrected result for the flags field in the examples (backport release-3.1.x)

[loki-gh-app]

Backport 60de788 from #14074

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What this PR does / why we need it:

Corrected wrong example result for the flags field. Without this change, the flags field is given with the wrong result making the example difficult for the reader to understand.

Which issue(s) this PR fixes:
Not directly associated with any current issue tickets.

Special notes for your reviewer:
N/A

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated (N/A)
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md (N/A)
• For Helm chart changes bump the Helm chart version in production/helm/loki/Chart.yaml and update production/helm/loki/CHANGELOG.md and production/helm/loki/README.md. Example PR (N/A)
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR (N/A)