Default to the Data tab for experiments that have started

[zackcl]

The experiment details page currently opens on the Design tab by default.

Once an experiment has started, the primary user goal is to monitor enrollment and metrics, not to review the setup. For this reason, experiments that have started (Running, Paused, Completed) should default to the Data tab, while experiments that have never started (Inactive) or archived should continue to default to the Design tab.

The tab order and navigation remain unchanged. Only the initially selected tab varies based on experiment state.

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Update: I closed the PR I opened since this seems like something we may want to discuss more.