fix: add missing bpmn-js styles

Author: jarekdanielak

bpmn-js-app/angular.json

@@ -24,6 +24,7 @@
             ],
             "styles": [
               "node_modules/bpmn-js/dist/assets/diagram-js.css",
+              "node_modules/bpmn-js/dist/assets/bpmn-js.css",
               "node_modules/bpmn-js/dist/assets/bpmn-font/css/bpmn.css",
               "src/styles.css"
             ],