chore (02-client): update err return genesis state validate

[solkorap7]

Description

The error return type is obsolete (4 years ago)

closes: #XXXX

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[gjermundgaraba]

Hi @solkorap7, while this could be nice to have, I am not very concerned about this for the genesis validation. But more importantly, most of the error types are incorrect. I believe this is not really worth spending too much time on, so I will close the PR for now.

For the future, I suggest you either find an existing issue, or open an issue for discussion before opening a PR. To make the maintenance burden lower we will likely require an issue for every PR.