Upgrade wrapper endpoint 'contract-offer' to 0.1.2

[ghost]

Pull Request

Contains necessary changes for the usecase endpoint 'contract-offer' to work with the EDC Connector in version 0.1.2.
Can be merged when the version upgrade in #392 was merged.

In consultation with @richardtreier, I assign the PR to @efiege.

Linked Issue(s)

• see API Wrapper: Use Case API Initiative (Ongoing) #182

PR is blocked by

• Feat/upgrade to 0.1.3 #392

Checklist

• I have formatted the title correctly and precisely
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and public classes/methods
• I have made corresponding changes to the documentation
• My changes generate no new warnings (performed checkstyle check locally)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have added/updated copyright headers

[richardtreier]

@efiege this is already in main, right?

[richardtreier]

Thank you, @timdahlmanns. These changes have been integrated into a previous PR and have been already merged into the main