Remove Vue delete for vue 3 migration

Vue.delete is no longer supported in Vue 3
has to be replaced with common mutation

app/assets/javascripts/ide/stores/modules/editor/mutations.js

@@ -2,6 +2,13 @@ import Vue from 'vue';
 import * as types from './mutation_types';
 import { getFileEditorOrDefault } from './utils';
 
+const deletePropertyAndReturnNewCopy = (source, property) => {
+  const fileEditorsCopy = { ...source };
+  delete fileEditorsCopy[property];
+
+  return fileEditorsCopy;
+};
+
 export default {
   [types.UPDATE_FILE_EDITOR](state, { path, data }) {
     const editor = getFileEditorOrDefault(state.fileEditors, path);
@@ -9,7 +16,7 @@ export default {
     Vue.set(state.fileEditors, path, Object.assign(editor, data));
   },
   [types.REMOVE_FILE_EDITOR](state, path) {
-    Vue.delete(state.fileEditors, path);
+    state.fileEditors = deletePropertyAndReturnNewCopy(state.fileEditors, path);
   },
   [types.RENAME_FILE_EDITOR](state, { path, newPath }) {
     const existing = state.fileEditors[path];
@@ -19,7 +26,7 @@ export default {
       return;
     }
 
-    Vue.delete(state.fileEditors, path);
+    state.fileEditors = deletePropertyAndReturnNewCopy(state.fileEditors, path);
     Vue.set(state.fileEditors, newPath, existing);
   },
 };