Remove duplicate frontend spec

The spec was identical to
`spec/frontend/vue_shared/droplab_dropdown_button_spec.js`, which is
there both in CE & EE, so I propose removing it

spec/frontend/vue_shared/components/droplab_dropdown_button_spec.js

-import { mount, createLocalVue } from '@vue/test-utils';
-
-import DroplabDropdownButton from '~/vue_shared/components/droplab_dropdown_button.vue';
-
-const mockActions = [
-  {
-    title: 'Foo',
-    description: 'Some foo action',
-  },
-  {
-    title: 'Bar',
-    description: 'Some bar action',
-  },
-];
-
-const createComponent = ({
-  size = '',
-  dropdownClass = '',
-  actions = mockActions,
-  defaultAction = 0,
-}) => {
-  const localVue = createLocalVue();
-
-  return mount(DroplabDropdownButton, {
-    localVue,
-    propsData: {
-      size,
-      dropdownClass,
-      actions,
-      defaultAction,
-    },
-  });
-};
-
-describe('DroplabDropdownButton', () => {
-  let wrapper;
-
-  beforeEach(() => {
-    wrapper = createComponent({});
-  });
-
-  afterEach(() => {
-    wrapper.destroy();
-  });
-
-  describe('data', () => {
-    it('contains `selectedAction` representing value of `defaultAction` prop', () => {
-      expect(wrapper.vm.selectedAction).toBe(0);
-    });
-  });
-
-  describe('computed', () => {
-    describe('selectedActionTitle', () => {
-      it('returns string containing title of selected action', () => {
-        wrapper.setData({ selectedAction: 0 });
-
-        expect(wrapper.vm.selectedActionTitle).toBe(mockActions[0].title);
-
-        wrapper.setData({ selectedAction: 1 });
-
-        expect(wrapper.vm.selectedActionTitle).toBe(mockActions[1].title);
-      });
-    });
-
-    describe('buttonSizeClass', () => {
-      it('returns string containing button sizing class based on `size` prop', done => {
-        const wrapperWithSize = createComponent({
-          size: 'sm',
-        });
-
-        wrapperWithSize.vm.$nextTick(() => {
-          expect(wrapperWithSize.vm.buttonSizeClass).toBe('btn-sm');
-
-          done();
-          wrapperWithSize.destroy();
-        });
-      });
-    });
-  });
-
-  describe('methods', () => {
-    describe('handlePrimaryActionClick', () => {
-      it('emits `onActionClick` event on component with selectedAction object as param', () => {
-        jest.spyOn(wrapper.vm, '$emit');
-
-        wrapper.setData({ selectedAction: 0 });
-        wrapper.vm.handlePrimaryActionClick();
-
-        expect(wrapper.vm.$emit).toHaveBeenCalledWith('onActionClick', mockActions[0]);
-      });
-    });
-
-    describe('handleActionClick', () => {
-      it('emits `onActionSelect` event on component with selectedAction index as param', () => {
-        jest.spyOn(wrapper.vm, '$emit');
-
-        wrapper.vm.handleActionClick(1);
-
-        expect(wrapper.vm.$emit).toHaveBeenCalledWith('onActionSelect', 1);
-      });
-    });
-  });
-
-  describe('template', () => {
-    it('renders default action button', () => {
-      const defaultButton = wrapper.findAll('.btn').at(0);
-
-      expect(defaultButton.text()).toBe(mockActions[0].title);
-    });
-
-    it('renders dropdown button', () => {
-      const dropdownButton = wrapper.findAll('.dropdown-toggle').at(0);
-
-      expect(dropdownButton.isVisible()).toBe(true);
-    });
-
-    it('renders dropdown actions', () => {
-      const dropdownActions = wrapper.findAll('.dropdown-menu li button');
-
-      Array(dropdownActions.length)
-        .fill()
-        .forEach((_, index) => {
-          const actionContent = dropdownActions.at(index).find('.description');
-
-          expect(actionContent.find('strong').text()).toBe(mockActions[index].title);
-          expect(actionContent.find('p').text()).toBe(mockActions[index].description);
-        });
-    });
-
-    it('renders divider between dropdown actions', () => {
-      const dropdownDivider = wrapper.find('.dropdown-menu .divider');
-
-      expect(dropdownDivider.isVisible()).toBe(true);
-    });
-  });
-});