[picnic] fix StaticImport

[Pankraz76]

• https://error-prone.picnic.tech/bugpatterns/StaticImport

related to:

• [picnic] fix NonStaticImport #5191

PS:
this the last PR, opening mainly for comparison reasons, thanks for contribution.

sorry for noisy spam...

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes

[Pankraz76]

consider reopen after enabler:

• [picnic] fix NonStaticImport #5191