feat(argo-cd): Support setting ArgoCD Notifications secret (#2577)

* chore(deps): update renovatebot/github-action action to v40.1.3 (#2573)

Co-authored-by: renovate[bot] <renovate[bot]@users.noreply.github.com>
Signed-off-by: ranrubin <ranrubin@gmail.com>

* feat(argo-cd): Support for existing Secret in ArgoCD Notifications, and ability to set its name.

Signed-off-by: ranrubin <ranrubin@gmail.com>

* feat(argo-cd): Pass Secret name to Notification controller

Signed-off-by: ranrubin <ranrubin@gmail.com>

* chore(deps): update renovatebot/github-action action to v40.1.4 (#2579)

Co-authored-by: renovate[bot] <renovate[bot]@users.noreply.github.com>
Signed-off-by: ranrubin <ranrubin@gmail.com>

* feat(argo-cd): Remove redundant useExistingSecret, and assume existence of a secret

Signed-off-by: ranrubin <ranrubin@gmail.com>

---------

Signed-off-by: ranrubin <ranrubin@gmail.com>
Co-authored-by: argoproj-renovate[bot] <161757507+argoproj-renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <renovate[bot]@users.noreply.github.com>

charts/argo-cd/templates/argocd-configs/argocd-notifications-secret.yaml

@@ -2,7 +2,7 @@
 apiVersion: v1
 kind: Secret
 metadata:
-  name: argocd-notifications-secret
+  name: {{ .Values.notifications.secret.name }}
   namespace: {{ .Release.Namespace | quote }}
   labels:
     {{- include "argo-cd.labels" (dict "context" . "component" .Values.notifications.name "name" .Values.notifications.name) | nindent 4 }}