[eks] [default StorageClass]: make default allowVolumeExpansion: true

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**Tell us about your request**
Currently when a new EKS cluster is created, a default storageClass is deployed. The default settings for this storageClass includes setting `allowVolumeExpansion: false`.

Is there any reason why this is set to false by default? It seems to me that expansion of volumes would be something fairly common, and having to patch the StorageClass to allow expansion is an extra step which make the process less dynamic.

Would it not make more sense for the default setting to be `allowVolumeExpansion: true` ?

The issue names no repository file, test, or entry point; begin by locating how EKS provisions its default StorageClass and checking Kubernetes support for volume expansion. Done means a newly created EKS cluster receives a default StorageClass with allowVolumeExpansion set to true.

Written by the indexing model from the issue text.