feat(helm): allow configuration of service trafficDistribution parameter

[frittentheke]

What this PR does / why we need it:
Allow configuration of service trafficDistribution parameter

Which issue(s) this PR fixes:
Fixes #19557

Special notes for your reviewer:
While this is about exposing a simple Kubernetes service parameter .... Looking at this again, after having just pushed a PR implementing this, I am wondering if trafficDistribution even helps in reducing the cross-AZ traffic:

Looking at https://grafana.com/docs/loki/latest/get-started/architecture/#loki-architecture ...

1. Write-Path - Ingesters are addressed via hashing of the log streams (https://grafana.com/docs/loki/latest/get-started/architecture/#write-path) and don't care about the service Endpoints?

2. Read-Path - Queries come in to the query-frontends and then go to the queriers and ingesters (for very recent data).
   Do the frontends actually use the service endpoints or also use the hash, again distributing queries to all instances in all AZs?

3. I also found an old issue, Availability zone local replication #5319, discussing exactly what I am trying to achieve: save on VERY expensive cross-AZ traffic.

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

[jkroepke]

Please run make helm-docs as well.

[jkroepke]

LGTM, I hope I get some fries now.

[frittentheke]

LGTM, I hope I get some fries now.
Hope that worked out for ya?

Would you kindly let them tests run to see if there is anything I missed or messed up?