Fix bug not all issues showing in Swimlanes

Always fetch issues when mounting epic lane
Changelog: fixed
EE: true

ee/app/assets/javascripts/boards/components/epic_lane.vue

@@ -102,9 +102,7 @@ export default {
     },
   },
   mounted() {
-    if (this.issuesCount === 0) {
-      this.fetchIssuesForEpic(this.epic.id);
-    }
+    this.fetchIssuesForEpic(this.epic.id);
   },
   methods: {
     ...mapActions(['updateBoardEpicUserPreferences', 'setError', 'fetchIssuesForEpic']),

ee/spec/frontend/boards/components/epic_lane_spec.js

@@ -13,6 +13,7 @@ describe('EpicLane', () => {
   let wrapper;
 
   const updateBoardEpicUserPreferencesSpy = jest.fn();
+  const fetchIssuesForEpicSpy = jest.fn();
 
   const findChevronButton = () => wrapper.findComponent(GlButton);
 
@@ -20,7 +21,7 @@ describe('EpicLane', () => {
     return new Vuex.Store({
       actions: {
         updateBoardEpicUserPreferences: updateBoardEpicUserPreferencesSpy,
-        fetchIssuesForEpic: jest.fn(),
+        fetchIssuesForEpic: fetchIssuesForEpicSpy,
       },
       state: {
         boardItemsByListId,
@@ -61,6 +62,16 @@ describe('EpicLane', () => {
     wrapper.destroy();
   });
 
+  describe('mounted', () => {
+    beforeEach(() => {
+      createComponent();
+    });
+
+    it('calls fetchIssuesForEpic action on mount', () => {
+      expect(fetchIssuesForEpicSpy).toHaveBeenCalledWith(expect.any(Object), mockEpic.id);
+    });
+  });
+
   describe('template', () => {
     beforeEach(() => {
       createComponent();