Trident Helm install fails with: <.Values.imagePullSecrets>: range can't iterate

• Astra Trident
• Helm Installations using private, on-prem registry (no Internet access)

Background:
For environments that do not allow direct access to the internet, a private, harbor container can be set up to use an on-premise registry service. Since a typical deployment (connected to external registry) uses a standard registry secret type, a custom secret is created for an on-prem file (called 'regcred' in this example) with the following  data structure:

"Registery Domain Name" - <domain_name.local>
Username
Password

Issue:
From Trident documentation: Deploy Trident operator using Helm (Offline mode), running the following install command may produce an error:

# helm install trident-operator netapp-trident/trident-operator --version 100.2502.0 --create-namespace -n trident-system --set imageRegistry=domain_name_example.local/itdevops --set imagePullSecrets=regcred