healthcheck: runner to return error

[karol-kokoszka]

Return error from healtcheck runner

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Please make sure that:

• Code is split to commits that address a single change
• Commit messages are informative
• Commit titles have module prefix
• Commit titles have issue nr. suffix

[Michal-Leszczynski]

I understand that this change is fixing the logging from run.Parallel. While we are at it, could we also change:

_ = parallel.Run(len(addresses), parallel.NoLimit, f, func(i int, err error) { // nolint: errcheck
        r.logger.Error(ctx, "Parallel hosts check failed", "", addresses[i], "error", err)
    })

so that we don't include an empty string in logging? It should be something like "host" instead.

[karol-kokoszka]

updated