fix(local): scope observability repo update (#22)

Update only the prometheus-community Helm repository during local observability setup instead of refreshing every configured repository.

Signed-off-by: Frank Spitulski <fspitulski@nvidia.com>

Author: FrankSpitulski

local/infra/scripts/setup-observability.sh

@@ -18,7 +18,7 @@ CLUSTERS="csc cpc-1 cpc-2"
 
 # Add Prometheus Helm repository
 helm repo add prometheus-community https://prometheus-community.github.io/helm-charts 2>/dev/null || true
-helm repo update >/dev/null
+helm repo update prometheus-community >/dev/null
 
 deploy_to_cluster() {
   local cluster="$1"