Traversing in the widget generation wizard without any field changes fails saying "Unable to process your request"

[TanyaM]

Description:
While generating a widget using the wizard if we come back to data provider configuration from chart configuration by clicking Back button, even though we don't do any changes in the data provider configuration, an error notification is shown and not possible to go to the chart configuration again.

Affected Product Version:
4.0.29-SNAPSHOT

Steps to reproduce:

1. Go to "Create Widget" from portal app and give a preferred name for the widget
2. Select "RDBMS Batch Data Provider" and leave all the default configurations and click Next
3. Once you are in the "Configure Chart" page click Back button
4. Then try to click Next button again without doing any modifications to the provider configuration

It fails saying "Unable to process your request"