Remove seed from examples

> I would remove passing in a seed in the examples (all around I guess), but I would also not show `set.seed()` in the package code examples. That level of detail makes the most sense to me in the example notebooks, not in individual function docs.

_Originally posted by @jashapiro in https://github.com/AlexsLemonade/rOpenScPCA/pull/23#discussion_r1930906488_

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This issue tracks updating examples in the `roxygen` comments to remove any seed setting or passing.

Inspect the package's roxygen comments and their code examples first. Remove seed setting and seed arguments from those examples, while leaving seed details for the example notebooks; done means the roxygen examples no longer set or pass seeds.

Written by the indexing model from the issue text.