loki update to 6.6.4-bb.5

Package Merge Request

Package Changes

Set default "prod" log retention to 1y.

Package MR

big-bang/product/packages/loki!257 (merged)

For Issue

Closes big-bang/product/packages/loki#190 (closed)

Upgrade Notices

By default, Loki retains logs FOREVER. To change this retention period, you can set retention_period as demonstrated in the Loki package's values.yaml.