fix: add conversion webhook settings and test for eks cluster

[afrancis101]

Description of your changes

This PR is written to fix issues encountered between v1beta1 and v1beta2 of the eks.aws.upbound.io resources. The issue encountered is:

conversion webhook for eks.aws.upbound.io/v1beta1, Kind=Cluster failed: cannot convert from the spoke version "v1beta1" to the hub version "v1beta2": cannot apply the PavedConversion for the "aws_eks_cluster" object: failed to convert the source map in mode "toEmbeddedObject" with source API version "*", target API version "v1beta2": value at the field path upgradePolicy must be []any, not "map[string]interface {}"

Fixes #

I have:

• Read and followed Crossplane's [contribution process].
• Run make generate and committed the results (ideally in a separate commit).
• Not made any manual changes to generated files, and verified this with make check-diff.

How has this code been tested