Switching between providers in widget generation wizard wipes out default data

[TanyaM]

Description:
If we switch to different providers in the "Configure Data Provider" step, some of the default data is wiped out. Also that makes it impossible to move to next step as there is no indication on what required fields are missing.

Affected Product Version:
4.0.29-SNAPSHOT

Steps to reproduce:

1. Go to Create Widget and give a preferred name for the widget
2. Select "Siddhi Store Data Provider" in the "Configure Data Provider" step
3. Then change the data provider to "RDBMS Batch Data Provider"

This will wipe out the query in the "Dynamic Query Generation Configuration" section.
If you click Next button after that it fails silently without giving any notification.
Following error in observed in the browser console.

bundle.js:74 Uncaught SyntaxError: Illegal return statement
at GadgetsGenerationWizard.handleNext (https://10.100.0.233:9643/portal/public/app/js/bundle.js:74:90287)
at r.handleClick (https://10.100.0.233:9643/portal/public/app/js/bundle.js:4:8503)
at Object.l (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:3393)
at Object.invokeGuardedCallback (https://10.100.0.233:9643/portal/public/app/js/bundle.js:36:4503)
at Object.invokeGuardedCallbackAndCatchFirstError (https://10.100.0.233:9643/portal/public/app/js/bundle.js:36:4620)
at p (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:4318)
at g (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:4786)
at A (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:4943)
at Array.forEach (native)
at v (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:4587)
at x (https://10.100.0.233:9643/portal/public/app/js/bundle.js:28:5623)
at Vr (https://10.100.0.233:9643/portal/public/app/js/bundle.js:36:18725)