BlueGreen rollout sync changes scale of both the stable and new ReplicaSets

[yossisolomon]

Checklist:

• I've included steps to reproduce the bug.
• I've included the version of argo rollouts.

Describe the bug

To Reproduce

• Create a BlueGreen rollout with any scale (replicas)
• Change replicas in new rollout version
• On sync, both the stable RS and the new RS will be in the new replicase (scaling in/out the stable RS connected to production)

Expected behavior

Only the new RS should have the new scale - this is a part of having a BlueGreen rollout (only promotion should lead to a change to production)

Screenshots

Version

We're running on 1.8.1 (here's the relevant code causing it as far as I can tell), but looking at the code in master it's still the same

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[zachaller]

I think this is by design, if production scales we scale canary/desired that why when the promtion happens their is enough pods available for the load. Essentially both are equal to the rollouts spec.replicas field.