[CM1-510] Popup added when trying to reject case from ER

As a user I want a pop up with Yes and No button to appear when I want to reject a case from ER.

Because I might have choosen reject by mistake and want to be able to stop the action.

When chosing “reject case” in case import window, and then clicking “Send as email”, then a popup window appear asking you to confirm the rejection.

If you do not wish to continue with rejecting the case, you can chose to Cancel.