Add Support for STS regional Endpoints

### What feature do you want to see added?

When adding an AWS Credential to Jenkins that includes a Role ARN, the plugin will only use the commercial STS endpoint (sts.amazonaws.com) to retrieve temporary credentials. This means you cannot specify a Role ARN if you are supplying credentials in a private network where an internet connection is not available.
The feature should dynamically select the appropriate STS Endpoint based region example,
If we try to connect the sts endpoint from the eu-west-1 region and the global endpoint isn't able to connect due to an internet connection it should try to connect region-based endpoint [ sts.eu-west-1.amazonaws.com ].

### Upstream changes

_No response_