Platform Observability - Loki chart repo deprecated and relocated

[andikemgitopsbot]

The repository was deprecated and moved to new link
source: https://github.com/grafana/helm-charts/tree/main/charts/loki

warning DEPRECATEDD - Loki chart
This chart was moved to https://github.com/grafana/loki/tree/main/production/helm/loki.

Please file any issues with the new chart on the [Grafana Loki](https://github.com/grafana/loki) repository.

The source code for this chart was removed from this repoistory after commit [b8a1b0cd](https://github.com/grafana/helm-charts/commit/b8a1b0cd8ffac1f5e6242d6aa1cba907cf2ec17f).

new location:
https://github.com/grafana/loki/tree/main/production/helm/loki