SMCP upgrade from 2.3 to 2.4 failed with "Observed a panic" and "populateExtensionProvidersConfig" errors in istio-operator pod logs

Issue

• SMCP failed to upgrade from 2.3 to 2.4 version. The istio-operator pod remains in crashloopbackoff state with below logs:

  $ oc get pods -n openshift-operators
  NAME                             READY  STATUS            RESTARTS  AGE
  istio-operator-76bdccfcf6-r4v52  0/1    crashloopbackoff  8         21m
  

  $ oc logs pod/istio-operator-76bdccfcf6-r4v52
  
  Output-omitted
  
  goroutine 2039 [running]:
  k8s.io/apimachinery/pkg/util/runtime.logPanic({0x1638920?, 0xc003229dd0})
        /remote-source/istio-operator/app/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:74 +0x99
  k8s.io/apimachinery/pkg/util/runtime.HandleCrash({0x0, 0x0, 0xc0017dc1c0?})
        /remote-source/istio-operator/app/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:48 +0x75
  panic({0x1638920, 0xc003229dd0})
        /usr/lib/golang/src/runtime/panic.go:884 +0x212
  github.com/maistra/istio-operator/pkg/apis/maistra/conversion.populateExtensionProvidersConfig(0xc002318980?, 
  0xc000a14218)