Description of problem:
Email Task does not allow full html content in Body attribute

Version-Release number of selected component (if applicable):
6.2.x, 6.3.0


How reproducible:
Always


Steps to Reproduce:
1.Create a simple process containing Start -> Email Task -> End
2. In Assignment for Email Task, try to add a full html content 
3. Try to save the Assignment

Actual results:
Save does not work, no log or message about why.


Expected results:
Save the content or report why that operation is not allowed