fix(gpu): add reproducibility in oprf uniformity test

[guillermo-oyarzun]

closes: please link all relevant issues

PR content/description

Check-list:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• Relevant issues are marked as resolved/closed, related issues are linked in the description
• Check for breaking changes (including serialization changes) and add them to commit message following the conventional commit specification

[github-actions]

✅ Backward-compat snapshot: everything looks good! No backward-compatibility issues detected.

[github-actions]

✅ Forward compatibility matrix unchanged: it still matches the committed baseline.

Matrix

Which released versions can load data produced by this branch. A ❌ is not a failure by itself: it only means forward compatibility is not (or no longer) provided for that type. What matters is whether it was reviewed.

TYPE	1.5.5	1.6.3	1.7.0
CompactPublicKey	❌	✅	✅
CompactPkeCrs	✅	✅	✅
ProvenCompactCiphertextList	❌	✅	✅