Fixed broken revision history

frontend/src/metabase/reference/Reference.css

+:root {
+    --subheader-color: #6CAFED;
+}
+
+:local(.subheader) {
+    composes: text-white pl4 pr3 flex align-center from "style";
+    position: absolute;
+    top: 0;
+    left: 0;
+    right: 0;
+    height: 40px;
+    background-color: var(--subheader-color);
+}
+
+:local(.subheaderButtons) {
+    composes: flex-align-right from "style";
+}
+
+:local(.subheaderButton) {
+    border: none;
+    color: var(--subheader-color);
+}
+
+:local(.saveButton) {
+    composes: mx1 from "style";
+}
+
+:local(.cancelButton) {
+    opacity: 0.5;
+}

frontend/src/metabase/reference/containers/ReferenceEntity.jsx

@@ -89,7 +89,7 @@ export default class EntityItem extends Component {
                             </div>
                             <div className={R.subheaderButtons}>
                                 <button className={cx("Button", "Button--white", "Button--small", R.subheaderButton, R.saveButton)} type="submit">SAVE</button>
-                                <button className={cx("Button", "Button--white", "Button--small", R.subheaderButton, R.cancelButton)} type="submit">CANCEL</button>
+                                <button className={cx("Button", "Button--white", "Button--small", R.subheaderButton, R.cancelButton)} onClick={endEditing}>CANCEL</button>
                             </div>
                         </div>
                     }

frontend/src/metabase/reference/containers/ReferenceRevisionsList.jsx

@@ -67,7 +67,7 @@ export default class RevisionHistoryApp extends Component {
             error
         } = this.props;
 
-        const entity = metric.id !== undefined ? metric : list;
+        const entity = metric.id ? metric : list;
 
         const empty = {
             icon: 'mine',
@@ -89,7 +89,7 @@ export default class RevisionHistoryApp extends Component {
                     </div>
                 </div>
                 <LoadingAndErrorWrapper loading={!error && loading} error={error}>
-                    { () => {console.log(tables); return Object.keys(revisions).length > 0 && tables[entity.table_id] ?
+                    { () => {console.log(revisions);console.log(tables); console.log(entity); return Object.keys(revisions).length > 0 && tables[entity.table_id] ?
                         <div className="wrapper wrapper--trim">
                             {Object.values(revisions)
                                 .map(revision => revision && revision.diff ?