CRAFTER-1183: RTE doesn't work inside repeat groups

1) Create a repeat group with an RTE
2) Write something inside the RTE
3) Save and close
4) Open the form again

The content will not appear inside the RTE (in IE)
- Fix in forms-engine.js

1) Create a repeat group with an RTE
2) Create another repeat group with an RTE

The form blocks. It's not able to do anything to it (in IE)
- Fix in insert-component.js