improve: sync script to detect if prune required before syncing

[thesuperzapper]

This PR improves the sync_argocd_apps.sh script so that it detects if resources need to be pruned before syncing, rather than doing a sync, and seeing if it throws a warning that resources require pruning.

We do this by additionally checking if there are any resources with requiresPruning: true when we get the status of the ArgoCD apps, and only prompting the user to prune there if there is at least one. We also print the list of resources that need to be pruned, to help the user decide.

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WARNING: DO NOT MERGE until argoproj/argo-cd#17188 is resolved

Note, we could work-around the upstream ArgoCD issue by looping over each resource that "requires pruning", and check if it has the argocd.argoproj.io/sync-options: Prune=false annotation.

However, this approach has two significant problems:

• It requires that the person running the sync script has a kubectl context with permission to get on pretty much every resource in the cluster.
• It will require potentially hundreds of get requests, one for each resource that ArgoCD thinks needs to be pruned (which will increase for some deployKF apps with the number of users, as we replicate resources like Secrets for each profile).