SERVER-99492 Implement $_internalUnpackBucket stage generation for tracked collections before ClusterAggregate::runAggregate

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• Closed

SERVER-99503 Detect when $_internalUnpackBucket is generated early and skip kickback generation step

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• Closed

SERVER-100002 Implement $_internalUnpackBucket stage generation for untracked collections in sharded cluster

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• Closed

SERVER-99511 Ensure that existing tests work with earlier-generated $_internalUnpackBucket stage

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• Closed

SERVER-101709 Centralize logic for checking viewless timeseries rewrite eligibility

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• Closed