Updated blob editor to work with instance

Instead of calling proxy methods on the root editor, we now call
methods directly on the instance.

app/assets/javascripts/blob/file_template_mediator.js

 import $ from 'jquery';
+import { Position } from 'monaco-editor';
+
 import Api from '~/api';
+import toast from '~/vue_shared/plugins/global_toast';
+import { __ } from '~/locale';
+import initPopover from '~/blob/suggest_gitlab_ci_yml';
 
 import { deprecatedCreateFlash as Flash } from '../flash';
+
 import FileTemplateTypeSelector from './template_selectors/type_selector';
 import BlobCiYamlSelector from './template_selectors/ci_yaml_selector';
 import DockerfileSelector from './template_selectors/dockerfile_selector';
 import GitignoreSelector from './template_selectors/gitignore_selector';
 import LicenseSelector from './template_selectors/license_selector';
 import MetricsDashboardSelector from './template_selectors/metrics_dashboard_selector';
-import toast from '~/vue_shared/plugins/global_toast';
-import { __ } from '~/locale';
-import initPopover from '~/blob/suggest_gitlab_ci_yml';
 
 export default class FileTemplateMediator {
   constructor({ editor, currentAction, projectId }) {
@@ -188,7 +191,14 @@ export default class FileTemplateMediator {
 
     this.editor.focus();
 
-    this.editor.navigateFileStart();
+    if (this.editor.navigateFileStart) {
+      // ACE. This will be removed and cleaned up
+      // in https://gitlab.com/gitlab-org/gitlab/-/issues/198610
+      this.editor.navigateFileStart();
+    } else {
+      // Editor Lite
+      this.editor.setPosition(new Position(1, 1));
+    }
   }
 
   findTemplateSelectorByKey(key) {

app/assets/javascripts/blob_edit/edit_blob.js

@@ -50,20 +50,20 @@ export default class EditBlob {
         const fileContentEl = document.getElementById('file-content');
         const form = document.querySelector('.js-edit-blob-form');
 
-        this.editor = new EditorLite();
+        const rootEditor = new EditorLite();
 
-        if (MarkdownExtension) {
-          this.editor.use(MarkdownExtension.default);
-        }
-
-        this.editor.createInstance({
+        this.editor = rootEditor.createInstance({
           el: editorEl,
           blobPath: fileNameEl.value,
           blobContent: editorEl.innerText,
         });
 
+        if (MarkdownExtension) {
+          rootEditor.use(MarkdownExtension.default, this.editor);
+        }
+
         fileNameEl.addEventListener('change', () => {
-          this.editor.updateModelLanguage(fileNameEl.value);
+          rootEditor.updateModelLanguage(fileNameEl.value);
         });
 
         form.addEventListener('submit', () => {