Ensure better output diagniostics if AUTHENTICATION_PLUGIN_FILE is not pointing to valid file

Type of change

• Bug Fix
• Feature

Does this introduce a change in the core logic?

• [Yes]

Does this introduce a change in the cloud provider implementation, if so which cloud?

• AWS
• Azure
• GCP
• IBM

Updates description?

Ensure there is a logged message showing what has actually happened if the file pointed to by AUTHENTICATION_PLUGIN_FILE does not exist.