fix: Loki chart fails to render proper YAML when add more than one ex…

[ngclinflows]

…tra manifest (#12910)

What this PR does / why we need it:
Just a small fix to resolve my issue.

Which issue(s) this PR fixes:
Fixes #12910

Special notes for your reviewer:
I didn't bumped Helm Chart version myself

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• 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
• 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
• 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

[CLAassistant]

All committers have signed the CLA.

[Jayclifford345]

Hi @ngclinflows, thanks for the contribution. Would you mind also adding a test config for this to the CI?
https://github.com/grafana/loki/tree/main/production/helm/loki/ci

[Jayclifford345]

LGTM