Trim global section to avoid empty line to be indented (#10204)

This fix prometheus.yml output display when using `kubectl get configmap prometheus-server`

Signed-off-by: Sylvain Rabot <s.rabot@lectra.com>

stable/prometheus/Chart.yaml

@@ -1,5 +1,5 @@
 name: prometheus
-version: 8.3.0
+version: 8.3.1
 appVersion: 2.6.0
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/

stable/prometheus/templates/server-configmap.yaml

@@ -11,7 +11,7 @@ data:
   {{ $key }}: |
 {{- if eq $key "prometheus.yml" }}
     global:
-{{ $root.Values.server.global | toYaml | indent 6 }}
+{{ $root.Values.server.global | toYaml | trimSuffix "\n" | indent 6 }}
 {{- end }}
 {{ toYaml $value | default "{}" | indent 4 }}
 {{- if eq $key "prometheus.yml" -}}