feat(helm): support templating in service account annotations (#4374)

Enables Helm template functions in serviceAccount.annotations.
Allowing dynamic values like AWS account IDs for [EKS IRSA role ARNs](https://docs.aws.amazon.com/eks/latest/userguide/associate-service-account-role.html).

Signed-off-by: Samuel Masuy <[email protected]>

Author: samuelmasuy

helm/aws-load-balancer-controller/templates/serviceaccount.yaml

@@ -8,7 +8,7 @@ metadata:
     {{- include "aws-load-balancer-controller.labels" . | nindent 4 }}
   {{- with .Values.serviceAccount.annotations }}
   annotations:
-    {{- toYaml . | nindent 4 }}
+    {{- tpl (toYaml .) $ | nindent 4 }}
   {{- end }}
 automountServiceAccountToken: {{ .Values.serviceAccount.automountServiceAccountToken }}
 {{- with .Values.serviceAccount.imagePullSecrets }}