Dangling lines automatic pairing change

[flo-dup]

Please check if the PR fulfills these requirements

• [x] 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? Setting a pairing key on a dangling line does not change the pairing status

What is the new behavior (if this is a feature change)? Setting a pairing key on a dangling line triggers

• if the dangling line was paired, an update on the corresponding tieLine, which is removed from network
• in all cases, we're looking for an unpaired dangling line which has the same pairing key to pair it with

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

• [x] Yes
• [x] No

If yes, please check if the following requirements are fulfilled

• [ ] The Breaking Change or Deprecated label has been added
• [ ] The migration steps are described in the following section

What changes might users need to make in their application due to this PR? (migration steps)

Other information: