BUG 10273 "No es posible navegar por todas las pestanias de..." SOLVED

- Missing translation in "Assignment rules" (DESIGNER>Task>Properties)
- Added validation to prevent errors
* Available from version ProcessMaker-2.0.46
Merge pull request #1169 from victorsl/BUG-10273

BUG 10273 "No es posible navegar por todas las pestanias de..." SOLVED