Fix contingency generator for AC computations

[annetill]

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• 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 ? If so, link to this issue using '#XXX' and skip the rest

No. Bug fix.

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

In case of a generator contingency, changing the generator control type is not enough because there is no link with the equation system. The link is between the status of the controller bus and the equation system.

What is the current behavior? (You can also link to an open issue here)

After applying a generator contingency, we have to check that all generators have switch off the voltage control or not. If yes, we change the controller bus status, that will lead to the update of the equation system.

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

Does this PR introduce a breaking change or deprecate an API? If yes, check the following:

• The Breaking Change or Deprecated label has been added
• The migration guide has been updated in the github wiki (What changes might users need to make in their application due to this PR?)

Other information:

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[sonarqubecloud]

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91.1% Coverage
0.0% Duplication