[SHIBUI-1030]

Removed unused imports.

backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/ConfigurationController.java

@@ -7,11 +7,9 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
-import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 
-import javax.mail.MessagingException;
 import java.util.stream.Collectors;
 
 /**