Fix scaling logic in reconcileNewMachineSetInPlace

[acumino]

What this PR does / why we need it:
Adds a check to ensure the new machine set is scaled up when the combined replicas of old and new machine sets are less than the desired deployment replicas. This basically ensures that if a machine is deleted manually from the old machine sets, a new machine should be created in the new machine set with the updated configuration.

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Release note:

Fixed an issue where deleting a machine from an old MachineSet could prevent proper scaling. The new MachineSet now scales up when total replicas (old + new) drop below the desired count, ensuring replacements are created with the updated configuration.