Move Jest shim for Element.innerText to dom_shims

**Why?**
This helps clean up our test_setup
https://gitlab.com/gitlab-org/gitlab/issues/33139

spec/frontend/helpers/dom_shims/index.js

 import './get_client_rects';
+import './inner_text';

spec/frontend/helpers/dom_shims/inner_text.js

+// workaround for JSDOM not supporting innerText
+// see https://github.com/jsdom/jsdom/issues/1245
+Object.defineProperty(global.Element.prototype, 'innerText', {
+  get() {
+    return this.textContent;
+  },
+  set(value) {
+    this.textContext = value;
+  },
+  configurable: true, // make it so that it doesn't blow chunks on re-running tests with things like --watch
+});

spec/frontend/test_setup.js

@@ -34,18 +34,6 @@ Vue.config.productionTip = false;
 
 Vue.use(Translate);
 
-// workaround for JSDOM not supporting innerText
-// see https://github.com/jsdom/jsdom/issues/1245
-Object.defineProperty(global.Element.prototype, 'innerText', {
-  get() {
-    return this.textContent;
-  },
-  set(value) {
-    this.textContext = value;
-  },
-  configurable: true, // make it so that it doesn't blow chunks on re-running tests with things like --watch
-});
-
 // convenience wrapper for migration from Karma
 Object.assign(global, {
   getJSONFixture,