Are credentials set?

I'm trying to figure out if this is feasible.

Ideally, I'd like to set the HTML elements to be readonly (and style with CSS, so it's apparent), if the credentials are supplied via environment variables. I am able to set the environment variables and make the API calls after saving blank values within the config node.

When I hit this breakpoint, I doesn't appear I'm able to discern if the credentials have been set and the input's are blank. Is there a way to tell or signal the UI that these were set already, so the UX isn't clunky?

For context, this is how the AWS SDK looks for credentials: