Update cluster nodes separately

### Describe the Feature

Hi.

I'm using this module in my cluster Docdb, but
when we change de family size the change is applying in both of them nodes. This action make de failover do not work and the application come down during the change.
Is the module is prepared to make this change separately on the nodes?

Regards

### Expected Behavior

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### Use Case

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### Describe Ideal Solution

I think that the module could make changes in nodes separately.

### Alternatives Considered

_No response_

### Additional Context

_No response_

Begin by reviewing the module's DocumentDB cluster configuration and how family-size changes are applied to cluster nodes. Compare the current behavior with AWS failover requirements; done means the change can be performed separately without taking the application down, with appropriate module-level verification.

Written by the indexing model from the issue text.