cleanup: defaultProps -> JS default params on our function components

React 19 drops defaultProps on function components. Converted the 9 of
ours that used it (App, Navigation, ReSendEmail, Reconnect, OAuthLoginButton,
PageHeader, Page, EditDocument, EditSubscription) to destructured default
params; App defaults userId/emailAddress in its withTracker instead (it
spreads {...props} widely). Class components keep defaultProps (still
supported). The only defaultProps warnings left are from the react-share
npm package (CreatedButton/Icon), not our code. REST smoke byte-identical.

imports/ui/pages/EditDocument/EditDocument.js

@@ -6,17 +6,13 @@ import Documents from '../../../api/Documents/Documents';
 import DocumentEditor from '../../components/DocumentEditor/DocumentEditor';
 import NotFound from '../NotFound/NotFound';
 
-const EditDocument = ({ doc, history }) => (doc ? (
+const EditDocument = ({ doc = null, history }) => (doc ? (
   <div className="EditDocument">
     <h4 className="page-header">{`Editing "${doc.title}"`}</h4>
     <DocumentEditor doc={doc} history={history} />
   </div>
 ) : <NotFound />);
 
-EditDocument.defaultProps = {
-  doc: null
-};
-
 EditDocument.propTypes = {
   doc: PropTypes.object,
   history: PropTypes.object.isRequired

imports/ui/pages/EditSubscription/EditSubscription.js

@@ -6,17 +6,13 @@ import Subscriptions from '../../../api/Subscriptions/Subscriptions';
 import SubscriptionEditor from '../../components/SubscriptionEditor/SubscriptionEditor';
 import NotFound from '../NotFound/NotFound';
 
-const EditSubscription = ({ doc, history }) => (doc ? (
+const EditSubscription = ({ doc = null, history }) => (doc ? (
   <div className="EditSubscription">
     <h4 className="page-header">{`Editing "${doc.title}"`}</h4>
     <SubscriptionEditor doc={doc} history={history} />
   </div>
 ) : <NotFound />);
 
-EditSubscription.defaultProps = {
-  doc: null
-};
-
 EditSubscription.propTypes = {
   doc: PropTypes.object,
   history: PropTypes.object.isRequired

imports/ui/pages/Page/Page.js

@@ -10,7 +10,7 @@ import { Helmet } from 'react-helmet-async';
 
 import './Page.scss';
 
-const Page = ({ title, subtitle, content }) => (
+const Page = ({ title, subtitle = '', content }) => (
   <div className="Page">
     <Helmet>
       <meta charSet="utf-8" />
@@ -21,10 +21,6 @@ const Page = ({ title, subtitle, content }) => (
   </div>
 );
 
-Page.defaultProps = {
-  subtitle: ''
-};
-
 Page.propTypes = {
   title: PropTypes.string.isRequired,
   subtitle: PropTypes.string,