CORE-4305 CORE-4307 CORE-4324 IPlantPromptDialog fix.

Updated the text field in IPlantPromptDialog to enable the OK button on key-up, since auto-validation happens on key-up.
Moved the "enter" key handling logic to its own key-down handler, since the field's cell consumes enter key events on key-up and key-press.
Added a validation check to the "enter" key handler.