Fix #8056: Validate solution presence in all Vulnerabilities

[gmrnlg1971]

Description

As part of resolving #8056, this PR adds a validation loop to DefaultVulnerabilitiesUnitTest in zap-extensions to strictly assert that getSolution() is not empty for any loaded vulnerability.

Testing

• Unit tests pass, proving that all currently active vulnerabilities have solutions.

[github-actions]

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[psiinon]

Checkmarx One – Scan Summary & Details – aee38b0a-89b0-4037-b55b-1ab4ab97776d

Great job! No new security vulnerabilities introduced in this pull request

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[thc202]

This is a duplicate of #7467.