Do not inherit credentials when setting a registry URL

[benzea]

Jenkins and plugins versions report

What Operating System are you using (both controller, and any agents involved in the problem)?

Linux

Reproduction steps

1. Set a registry with credentials globally.
2. Specify a registryUrl in a docker {} block without credentials

Expected Results

Do not use the globally configured registry credentials.

Actual Results

Inherits the globally configured value.

Anything else?

I suppose, it could make sense to also have a way to simply disable the use of a globally configured registry in case one wants to use an image that already exists locally.

Are you interested in contributing a fix?

No response