[Bug][Go]: Metrics incremented in Setup methods are not recalled.

What happened?

Because the ParDo Setup context is uncached metrics initialized in Setup are lost, which is unexpected. Work done in setup, while logically outside of a bundle, will be under the context of the first bundle to execute that transform.

So there needs to be a way to transfer/extract the metrics from the Setup context so they are recorded back to the runner.

Issue Priority

Priority: 3 (minor)

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