Fix bug where decoding stringdata modified the existing object directly

Solution: when decoding, operate on a copy of the existing object's data

Ref: https://issues.redhat.com/browse/ACM-8739
Signed-off-by: Jeffrey Luo <jeluo@redhat.com>

controllers/configurationpolicy_controller.go

@@ -2410,16 +2410,16 @@ func handleSingleKey(
  }
 
  if key == "stringData" && existingObj.GetKind() == "Secret" {
- // override automatic conversion from stringData to data prior to evaluation
- existingValue = existingObj.UnstructuredContent()["data"]
-
+ // override automatic conversion from stringData to data before evaluation
  encodedValue, _, err := unstructured.NestedStringMap(existingObj.Object, "data")
  if err != nil {
  message := "Error accessing encoded data"
 
  return message, false, mergedValue, false
  }
 
+ existingValue = make(map[string]interface{}, len(encodedValue))
+
  for k, value := range encodedValue {
  decodedVal, err := base64.StdEncoding.DecodeString(value)
  if err != nil {