Conform more of the code base to strict null checking (#10147)

* Conform more of the code base to strict null checking

* More strict fixes

* More strict work

* Fix missing optional type

* Iterate

src/components/views/room_settings/AliasSettings.tsx

@@ -336,7 +336,7 @@ export default class AliasSettings extends React.Component<IProps, IState> {
         return this.state.localAliases.filter((alias) => !altAliases.includes(alias));
     }
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         const mxClient = this.context;
         const localDomain = mxClient.getDomain();
         const isSpaceRoom = mxClient.getRoom(this.props.roomId)?.isSpaceRoom();

src/components/views/room_settings/RoomProfileSettings.tsx

@@ -218,7 +218,7 @@ export default class RoomProfileSettings extends React.Component<IProps, IState>
         reader.readAsDataURL(file);
     };
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         let profileSettingsButtons;
         if (this.state.canSetName || this.state.canSetTopic || this.state.canSetAvatar) {
             profileSettingsButtons = (

src/components/views/room_settings/RoomPublishSetting.tsx

@@ -62,7 +62,7 @@ export default class RoomPublishSetting extends React.PureComponent<IProps, ISta
         });
     }
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         const client = MatrixClientPeg.get();
 
         const room = client.getRoom(this.props.roomId);

src/components/views/room_settings/UrlPreviewSettings.tsx

@@ -41,7 +41,7 @@ export default class UrlPreviewSettings extends React.Component<IProps> {
         dis.fire(Action.ViewUserSettings);
     };
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         const roomId = this.props.room.roomId;
         const isEncrypted = MatrixClientPeg.get().isRoomEncrypted(roomId);