Refactor showStagedIcon property's behavior to match its name

Previously, the `showStagedIcon` property was doing the opposite
of what its name suggested. It was rendering the staged icon when
`showStagedIcon` was `false` and rendering the regular icon when
it was `true`.

app/assets/javascripts/ide/components/file_row_extra.vue

@@ -86,7 +86,7 @@ export default {
       v-else-if="showChangedFileIcon"
       :file="file"
       :show-tooltip="true"
-      :show-staged-icon="true"
+      :show-staged-icon="false"
     />
     <new-dropdown
       :type="file.type"

app/assets/javascripts/vue_shared/components/changed_file_icon.vue

@@ -24,7 +24,7 @@ export default {
     showStagedIcon: {
       type: Boolean,
       required: false,
-      default: false,
+      default: true,
     },
     size: {
       type: Number,
@@ -41,7 +41,7 @@ export default {
     changedIcon() {
       // False positive i18n lint: https://gitlab.com/gitlab-org/frontend/eslint-plugin-i18n/issues/26
       // eslint-disable-next-line @gitlab/i18n/no-non-i18n-strings
-      const suffix = !this.file.changed && this.file.staged && !this.showStagedIcon ? '-solid' : '';
+      const suffix = !this.file.changed && this.file.staged && this.showStagedIcon ? '-solid' : '';
 
       return `${getCommitIconMap(this.file).icon}${suffix}`;
     },

changelogs/unreleased/refactor-showStagedIcon.yml

+---
+title: Refactor showStagedIcon property to reflect the behavior its name represents.
+merge_request: 32333
+author: Arun Kumar Mohan
+type: other

spec/frontend/vue_shared/components/changed_file_icon_spec.js

@@ -106,12 +106,10 @@ describe('Changed file icon', () => {
     expect(findIcon().props('size')).toBe(size);
   });
 
-  // NOTE: It looks like 'showStagedIcon' behavior is backwards to what the name suggests
-  // https://gitlab.com/gitlab-org/gitlab-ce/issues/66071
   it.each`
     showStagedIcon | iconName                 | desc
-    ${false}       | ${'file-modified-solid'} | ${'with showStagedIcon false, renders staged icon'}
-    ${true}        | ${'file-modified'}       | ${'with showStagedIcon true, renders regular icon'}
+    ${true}        | ${'file-modified-solid'} | ${'with showStagedIcon true, renders staged icon'}
+    ${false}       | ${'file-modified'}       | ${'with showStagedIcon false, renders regular icon'}
   `('$desc', ({ showStagedIcon, iconName }) => {
     factory({
       file: stagedFile(),