fix: 3 locations with return undefined (not compatible with React 17)

app/components/Analytics.js

@@ -9,7 +9,9 @@ type Props = {
 
 export default class Analytics extends React.Component<Props> {
   componentDidMount() {
-    if (!env.GOOGLE_ANALYTICS_ID) return;
+    if (!env.GOOGLE_ANALYTICS_ID) {
+      return null;
+    }
 
     // standard Google Analytics script
     window.ga =

app/menus/NewDocumentMenu.js

@@ -25,7 +25,7 @@ function NewDocumentMenu() {
   const can = policies.abilities(team.id);
 
   if (!can.createDocument) {
-    return;
+    return null;
   }
 
   if (singleCollection) {

app/menus/NewTemplateMenu.js

@@ -23,7 +23,7 @@ function NewTemplateMenu() {
   const can = policies.abilities(team.id);
 
   if (!can.createDocument) {
-    return;
+    return null;
   }
 
   return (