Add option to skip similar nodegroup recomputation

[rrangith]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Related to #6940

This recomputation used to only occur when the bestOption NodeGroup did not exist, but was changed in #5802. There are cases where an expander could modify the bestOption's similar nodegroups, such as custom logic in the gRPC expander.

In cases like this, we should have a CLI option to trust expander’s similar nodegroups and skip the recomputation as long as the bestOption nodegroup exists. If it doesn’t exist, then we can create it and compute the similar options (I am also open to changing the PR to skipping recomputation when the nodegroup does not exist too).

If a user does not enable this option, then by default the behaviour will stay the same. This will only skip similar nodegroup recomputation for users who enable this option.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Added `skip-similar-node-group-recomputation` flag. If enabled, skips similar NodeGroup recomputation for the best option returned by the expander during scaleup.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: rrangith
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[k8s-ci-robot]

PR needs rebase.

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