Unable to disable minio when loki.strategy is set to "scalable" and not setting values for both endpoint and region

Description:

When using the loki subchart and utilizing IRSA and EKS, we needed to remove what would be templated by .Values.loki.objectStorage.endpoint` in our loki config in the child chart. To fit our use case we need the ability to set in this file:

1. loki.strategy to "scalable"
2. not define loki.objectStorage.endpoint
3. define loki.objectStorage.region

Basically, we don't need minio and our loki + irsa config didn't work with endpoint defined.

We have a workaround for this logic currently:

To ensure that minio is disabled, we needed to set loki.objectStorage.endpoint and loki.objectStorage.region, and then also pass in values.loki.storage.s3.endpoint: "" to not break our loki config file

loki:
  enabled: true
  strategy: "scalable"
  objectStorage:
    endpoint: s3.$region.amazonaws.com
    region: $region
    bucketNames:
      chunks: $bucket
      ruler: $bucket
      admin: $bucket
  values:
    serviceAccount:
      annotations: 
        eks.amazonaws.com/role-arn: $iam_role_arn
    loki:
      storage:
        s3:
          endpoint: ""