Update configuring-network-settings.md

[casals]

Why:

Fixes #156 (partially - PR 2 of 2)

What's being changed:

Added a Note box at the end of the page to make it clear that we do not support multiple network adapters on GHES.

Additional information

I referenced GHES with the variable defined by data/variables/product/prodname_ghe_server . If this is not the correct product variable to use in this case, please reference the correct one as a required change to this PR.

Check off the following:

• All of the tests are passing.
• I have reviewed my changes in staging.
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[janiceilene]

Sorry about this one @casals! Notes aren't supported in map topic pages like this one. I think the note you added in #208 will be sufficient to fix up #156. So I'm going to close this one out 💖