Adapted network UI to the new config HTTP API

[teclator]

Problem

Short description of the original problem.

• Bugzilla link
• openQA link
• Links to other related pull requests

Solution

Short description of the fix.

Testing

• Added a new unit test
• Tested manually

Screenshots

If the fix affects the UI attach some screenshots here.

Documentation

Remember to look at it from the user's perspective. Yes you have made the compiler happy.
But will the humans even know about your contribution? Sometimes they cannot miss it,
other times they need advertisement and explanation.

Look for relevant sections and adjust:

• The description parts of the JSON schema
• Is the CLI affected? See cli.md for a complete overview,
  change the /// comments (rust doc)
  and update the .md with cargo xtask markdown
• https://agama-project.github.io/ (source)
• Run: git ls-files '*.md'