argo-cd: Allow External Redis endpoint from secret #3735

Is your feature request related to a problem?

We are using Argo CD with AWS Elasticache, our Elasticache is provisioned via crossplane alongside the chart.

To be able to correctly point Argo we need to do two installs, or have Elasticache created separately because of the endpoint.
With this change we allow the redis endpoint when using externalRedis to be passed from the secret, it will be up to the user to ensure it is in host:port format

Related helm chart

argo-cd

Describe the solution you'd like

Being able to configure argo-cd to read redis endpoint from a secret.

Describe alternatives you've considered

No response

Additional context

No response