[Bug]: http and httppost transform can't reach underscored proxies

### Apache Hop version?

2.18.1

### Java version?

21

### Operating system

Windows

### What happened?

it's a minor issue as it theoretically isn't an allowed DNS hostname

### Issue Priority

Priority: 2

### Issue Component

Component: Transforms

Start by reproducing the issue in the HTTP and HTTP Post transforms on Windows with a proxy hostname containing underscores. Trace how each transform resolves and reaches the proxy; done means both transforms can connect to that proxy without breaking valid proxy handling.

Written by the indexing model from the issue text.