Fix LimitViolation data for three-windings transformers

[olperr1]

Please check if the PR fulfills these requirements

• [X] The commit message follows our guidelines
• [X] 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?

Bug fix

What is the current behavior?

When a LimitViolation is detected on a ThreeWindingsTransformer.Leg, it contains the following data:

• subjectId: the ID of the corresponding LfLegBranch;
• side: ONE (corresponding to the LfLegBranch side on which the limits are set. On side TWO there is the star bus)

For instance, if a LimitViolation is detected on the leg 2 of the ThreeWindingsTransformer "3wt", these data are respectively "3wt_leg_2" and ONE.

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

It now contains the following data:

• subjectId: the ID of the ThreeWindingsTransformer
• side: the leg's side.

For the previous example, the data are now respectively: "3wt" and TWO.

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

• [ ] Yes
• [X] No

Other information:

[sonarcloud[bot]]

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 SonarCloud