Move R,X characteristics from LineCharaceristics to Branch interface

[alicecaron]

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)
• A PR or issue has been opened in all impacted repositories (if any)

Does this PR already have an issue describing the problem?
Fixes #3521

What kind of change does this PR introduce?

Refacto, no functionnal change. TieLine are still not able to update R and X, an error is thrown.

What is the current behavior?

What is the new behavior (if this is a feature change)?

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

• Yes
• 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)

• Implementations of Branch interface should now implement getR/setR/getX/setX methods
• Implementations of LineCharacteristics should no longer implement getR/getX methods
• Implementations of MutableLineCharacteristics should no longer implement setR/setX methods

Other information:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud