flaky public key aggregation test

Discovered while working on #49 , posted in a [comment](https://github.com/ChainSafe/blst-z/pull/49#issuecomment-3347781048) in that PR, but the gist is as the quote says:

> Seems like there's a [flaky test](https://github.com/ChainSafe/blst-z/blob/706a1392e4e711fce0a012e9c6c099f09dca7ede/bun/test/unit/aggregatePublicKeys.test.ts#L21-L35) in aggregating public keys, not quite sure what's the issue just yet. Had to [re-run the macOS job 3 times](https://github.com/ChainSafe/blst-z/actions/runs/18102246281/job/51509413632) for CI to pass. Creating an issue for this.

The failure is on aggregation and not the validation, and the public key aggregation binding is only used in this test. Perhaps the implementation needs to be checked, though FWIW, the zig native test works fine, so maybe something to do with the TS side?