Remove unreferenced list_collapsed component

`git grep -E import.*list_collapsed` shows this isn't
being used.

app/assets/javascripts/ide/components/commit_sidebar/list_collapsed.vue

-<script>
-import { GlIcon } from '@gitlab/ui';
-import tooltip from '~/vue_shared/directives/tooltip';
-import { sprintf, n__, __ } from '~/locale';
-
-export default {
-  components: {
-    GlIcon,
-  },
-  directives: {
-    tooltip,
-  },
-  props: {
-    files: {
-      type: Array,
-      required: true,
-    },
-    iconName: {
-      type: String,
-      required: true,
-    },
-    title: {
-      type: String,
-      required: true,
-    },
-  },
-  computed: {
-    addedFilesLength() {
-      return this.files.filter(f => f.tempFile).length;
-    },
-    modifiedFilesLength() {
-      return this.files.filter(f => !f.tempFile).length;
-    },
-    addedFilesIconClass() {
-      return this.addedFilesLength ? 'multi-file-addition' : '';
-    },
-    modifiedFilesClass() {
-      return this.modifiedFilesLength ? 'multi-file-modified' : '';
-    },
-    additionsTooltip() {
-      return sprintf(
-        n__('1 %{type} addition', '%{count} %{type} additions', this.addedFilesLength),
-        {
-          type: this.title.toLowerCase(),
-          count: this.addedFilesLength,
-        },
-      );
-    },
-    modifiedTooltip() {
-      return sprintf(
-        n__('1 %{type} modification', '%{count} %{type} modifications', this.modifiedFilesLength),
-        {
-          type: this.title.toLowerCase(),
-          count: this.modifiedFilesLength,
-        },
-      );
-    },
-    titleTooltip() {
-      return sprintf(__('%{title} changes'), { title: this.title });
-    },
-    additionIconName() {
-      return this.title.toLowerCase() === 'staged' ? 'file-addition-solid' : 'file-addition';
-    },
-    modifiedIconName() {
-      return this.title.toLowerCase() === 'staged' ? 'file-modified-solid' : 'file-modified';
-    },
-  },
-};
-</script>
-
-<template>
-  <div class="multi-file-commit-list-collapsed text-center">
-    <div
-      v-tooltip
-      :title="titleTooltip"
-      data-container="body"
-      data-placement="left"
-      class="gl-mb-5"
-    >
-      <gl-icon v-once :name="iconName" :size="18" />
-    </div>
-    <div
-      v-tooltip
-      :title="additionsTooltip"
-      data-container="body"
-      data-placement="left"
-      class="gl-mb-3"
-    >
-      <gl-icon :name="additionIconName" :size="18" :class="addedFilesIconClass" />
-    </div>
-    {{ addedFilesLength }}
-    <div
-      v-tooltip
-      :title="modifiedTooltip"
-      data-container="body"
-      data-placement="left"
-      class="gl-mt-3 gl-mb-3"
-    >
-      <gl-icon :name="modifiedIconName" :size="18" :class="modifiedFilesClass" />
-    </div>
-    {{ modifiedFilesLength }}
-  </div>
-</template>

locale/gitlab.pot

@@ -1062,16 +1062,6 @@ msgstr ""
 msgid "0t1DgySidms"
 msgstr ""
 
-msgid "1 %{type} addition"
-msgid_plural "%{count} %{type} additions"
-msgstr[0] ""
-msgstr[1] ""
-
-msgid "1 %{type} modification"
-msgid_plural "%{count} %{type} modifications"
-msgstr[0] ""
-msgstr[1] ""
-
 msgid "1 Day"
 msgid_plural "%d Days"
 msgstr[0] ""

spec/frontend/ide/components/commit_sidebar/list_collapsed_spec.js

-import Vue from 'vue';
-import { createComponentWithStore } from 'helpers/vue_mount_component_helper';
-import { createStore } from '~/ide/stores';
-import listCollapsed from '~/ide/components/commit_sidebar/list_collapsed.vue';
-import { file } from '../../helpers';
-import { removeWhitespace } from '../../../helpers/text_helper';
-
-describe('Multi-file editor commit sidebar list collapsed', () => {
-  let vm;
-  let store;
-
-  beforeEach(() => {
-    store = createStore();
-
-    const Component = Vue.extend(listCollapsed);
-
-    vm = createComponentWithStore(Component, store, {
-      files: [
-        {
-          ...file('file1'),
-          tempFile: true,
-        },
-        file('file2'),
-      ],
-      iconName: 'staged',
-      title: 'Staged',
-    });
-
-    vm.$mount();
-  });
-
-  afterEach(() => {
-    vm.$destroy();
-  });
-
-  it('renders added & modified files count', () => {
-    expect(removeWhitespace(vm.$el.textContent).trim()).toBe('1 1');
-  });
-
-  describe('addedFilesLength', () => {
-    it('returns an length of temp files', () => {
-      expect(vm.addedFilesLength).toBe(1);
-    });
-  });
-
-  describe('modifiedFilesLength', () => {
-    it('returns an length of modified files', () => {
-      expect(vm.modifiedFilesLength).toBe(1);
-    });
-  });
-
-  describe('addedFilesIconClass', () => {
-    it('includes multi-file-addition when addedFiles is not empty', () => {
-      expect(vm.addedFilesIconClass).toContain('multi-file-addition');
-    });
-
-    it('excludes multi-file-addition when addedFiles is empty', () => {
-      vm.files = [];
-
-      expect(vm.addedFilesIconClass).not.toContain('multi-file-addition');
-    });
-  });
-
-  describe('modifiedFilesClass', () => {
-    it('includes multi-file-modified when addedFiles is not empty', () => {
-      expect(vm.modifiedFilesClass).toContain('multi-file-modified');
-    });
-
-    it('excludes multi-file-modified when addedFiles is empty', () => {
-      vm.files = [];
-
-      expect(vm.modifiedFilesClass).not.toContain('multi-file-modified');
-    });
-  });
-});