Diverse adjustements for update of Szenarienreport

[lindnemi]

• The model choses 2 cluster for FR and 2 for IT, instead of 3 IT and 1 FR as specified in the config. this has been aligned

TBC

Before asking for a review for this PR make sure to complete the following checklist:

• Workflow with target rule ariadne_all completes without errors
• The logic of export_ariadne_variables has been adapted to the changes
• One or several figures that validate the changes in the PR have been posted as a comment
• A brief description of the changes has been added to Changelog.md
• The latest main has been merged into the PR
• The config has a new prefix of the format YYYYMMDDdescriptive_title