Handle invalid API resources in discovery

[wiltonsr]

Solution based in a similar issue fixed in helm: helm/helm#6361

To reproduce the problem, just deploy an apiservice

$ oc apply -f https://raw.githubusercontent.com/kubernetes/sample-apiserver/master/artifacts/example/apiservice.yaml

This gonna create an error in your cluster

$ oc api-resources > /dev/null
error: unable to retrieve the complete list of server APIs: wardle.example.com/v1alpha1: the server is currently unable to handle the request

After this, the Spark Operator pod will stop with the same error above.

This PR prevents this using the IsGroupDiscoveryFailedError method.

[google-cla]

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