Fix up for issues bulk assignment test.

app/assets/javascripts/issues-bulk-assignment.js.es6

@@ -69,15 +69,17 @@
 
     getUnmarkedIndeterminedLabels() {
       const result = [];
-      const elements = this.getElement('.labels-filter .is-indeterminate');
-      const labelsToKeep = elements.map((el) => labelsToKeep.push($(el).data('labelId')));
-      const selectedLabels = this.getLabelsFromSelection()
-        .forEach(() => {
-          const id = selectedLabels[j];
+      const labelsToKeep = [];
+
+      this.getElement('.labels-filter .is-indeterminate')
+        .each((i, el) => labelsToKeep.push($(el).data('labelId')));
+
+      this.getLabelsFromSelection().forEach((id) => {
         if (labelsToKeep.indexOf(id) === -1) {
           result.push(id);
         }
       });
+
       return result;
     }