fix(data wizard): avoid class cast exception when switching data type (#2412)

* The method 'refresh databinding' was called twice when switching to
Java object data type -> the 'handleValueChange' method was called a
second time, and the second time the else block was used -> a Data with
the wrong type was created.

[STUDIO-3609](https://bonitasoft.atlassian.net/browse/STUDIO-3609)

bundles/plugins/org.bonitasoft.studio.data/src/org/bonitasoft/studio/data/ui/wizard/DataWizardPage.java

@@ -259,7 +259,6 @@ public class DataWizardPage extends WizardPage implements IBonitaVariableContext
                 javaData.setClassName(List.class.getName());
                 copyDataFeature(javaData);
                 data = javaData;
-                updateDatabinding();
             } else if (newType instanceof XMLType && !(data instanceof XMLData)) {
                 final XMLData xmlData = ProcessFactory.eINSTANCE.createXMLData();
                 xmlData.setDataType(newType);