Fix filtering board by Started milestone

Changelog: fixed

ee/app/assets/javascripts/boards/constants.js

@@ -46,11 +46,6 @@ export const IterationFilterType = {
   current: 'Current',
 };
 
-export const MilestoneFilterType = {
-  any: 'Any',
-  none: 'None',
-};
-
 export const WeightFilterType = {
   none: 'None',
 };

spec/frontend/boards/boards_util_spec.js

-import { formatIssueInput, filterVariables } from '~/boards/boards_util';
+import { formatIssueInput, filterVariables, FiltersInfo } from '~/boards/boards_util';
+import { FilterFields } from '~/boards/constants';
 
 describe('formatIssueInput', () => {
   const issueInput = {
@@ -149,4 +150,40 @@ describe('filterVariables', () => {
 
     expect(result).toEqual(expected);
   });
+
+  it.each([
+    [
+      'converts milestone wild card',
+      {
+        filters: {
+          milestoneTitle: 'Started',
+        },
+        expected: {
+          milestoneWildcardId: 'STARTED',
+          not: {},
+        },
+      },
+    ],
+    [
+      'converts assignee wild card',
+      {
+        filters: {
+          assigneeUsername: 'Any',
+        },
+        expected: {
+          assigneeWildcardId: 'ANY',
+          not: {},
+        },
+      },
+    ],
+  ])('%s', (_, { filters, issuableType = 'issue', expected }) => {
+    const result = filterVariables({
+      filters,
+      issuableType,
+      filterInfo: FiltersInfo,
+      filterFields: FilterFields,
+    });
+
+    expect(result).toEqual(expected);
+  });
 });