fix(helm): missing s3 field in lokiStorageConfig templated value

[peem5210]

What this PR does / why we need it:
Omitting the s3 field in lokiStorageConfig prevents the Loki backend from connecting to external S3-compatible storage (e.g., MinIO or Ceph) because it’s used to render the common Loki configuration.

Which issue(s) this PR fixes:
Fixes #18790

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
  • 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
• 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.

[jkroepke]

I see, it's omit in 294 not available as as block.

LGTM

[peem5210]

@jkroepke Thanks for the review and the LGTM! As a first-time Loki contributor, is there anything else needed from my side before this can be approved/merged?

[jkroepke]

Hey @peem5210

CI is green, so currently looks good. We have a merge window each Monday for a limited count of PRs. If you PR is not merged today, it will be merged on next monday.

[Jayclifford345]

LGTM!