fix(BpmnRules): disallow boundary event as messageFlow target

closes #1300

Author: MaxTru

lib/features/rules/BpmnRules.js

@@ -280,6 +280,7 @@ function isMessageFlowSource(element) {
 function isMessageFlowTarget(element) {
   return (
     is(element, 'bpmn:InteractionNode') &&
+    !is(element, 'bpmn:BoundaryEvent') &&
     !isForCompensation(element) && (
       !is(element, 'bpmn:Event') || (
         is(element, 'bpmn:CatchEvent') &&

test/spec/features/rules/BpmnRulesSpec.js

@@ -656,7 +656,7 @@ describe('features/modeling/rules - BpmnRules', function() {
 
       expectCanConnect('Task_in_OtherProcess', 'BoundaryEvent_on_SubProcess', {
         sequenceFlow: false,
-        messageFlow: true,
+        messageFlow: false,
         association: false,
         dataAssociation: false
       });