Move three windings transformers, dangling lines and voltage levels with unknown buses in network area diagram

[massimo-ferraro]

Please check if the PR fulfills these requirements

• [ ] The commit message follows our guidelines
• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem? no

What kind of change does this PR introduce? feature

What is the current behavior? Three windings transformers, dangling lines and voltage levels with unknown buses are not correctly moved

What is the new behavior (if this is a feature change)? Three windings transformers, dangling lines and voltage levels with unknown buses can be moved

Does this PR introduce a breaking change or deprecate an API?

• [ ] Yes
• [X] No