fix: explicity set registry for k8s-sidecar iamge

Signed-off-by: yellowhat <1692490+yellowhat@users.noreply.github.com>

Author: yellowhat

production/helm/loki/values.yaml

@@ -3971,7 +3971,7 @@ extraObjects: null
 sidecar:
   image:
     # -- The Docker registry and image for the k8s sidecar
-    repository: kiwigrid/k8s-sidecar
+    repository: docker.io/kiwigrid/k8s-sidecar
     # -- Docker image tag
     tag: 1.30.7
     # -- Docker image sha. If empty, no sha will be used