Migrate AuthFooter to TypeScript

src/components/views/auth/AuthBody.tsx

@@ -19,7 +19,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.AuthBody")
 export default class AuthBody extends React.PureComponent {
-    render() {
+    public render(): React.ReactNode {
         return <div className="mx_AuthBody">
             { this.props.children }
         </div>;

src/components/views/auth/AuthFooter.tsx

@@ -22,7 +22,7 @@ import { replaceableComponent } from "../../../utils/replaceableComponent";
 
 @replaceableComponent("views.auth.AuthFooter")
 export default class AuthFooter extends React.Component {
-    render() {
+    public render(): React.ReactNode {
         return (
             <div className="mx_AuthFooter">
                 <a href="https://matrix.org" target="_blank" rel="noreferrer noopener">{ _t("powered by Matrix") }</a>