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/dialogs/security/AccessSecretStorageDialog.tsx

@@ -268,7 +268,7 @@ export default class AccessSecretStorageDialog extends React.PureComponent<IProp
         }
     }
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         const hasPassphrase =
             this.props.keyInfo &&
             this.props.keyInfo.passphrase &&

src/components/views/dialogs/security/ConfirmDestroyCrossSigningDialog.tsx

@@ -33,7 +33,7 @@ export default class ConfirmDestroyCrossSigningDialog extends React.Component<IP
         this.props.onFinished(false);
     };
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         return (
             <BaseDialog
                 className="mx_ConfirmDestroyCrossSigningDialog"

src/components/views/dialogs/security/CreateCrossSigningDialog.tsx

@@ -168,7 +168,7 @@ export default class CreateCrossSigningDialog extends React.PureComponent<IProps
         this.props.onFinished(false);
     };
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         let content;
         if (this.state.error) {
             content = (

src/components/views/dialogs/security/RestoreKeyBackupDialog.tsx

@@ -308,7 +308,7 @@ export default class RestoreKeyBackupDialog extends React.PureComponent<IProps,
         }
     }
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         const backupHasPassphrase =
             this.state.backupInfo &&
             this.state.backupInfo.auth_data &&

src/components/views/dialogs/security/SetupEncryptionDialog.tsx

@@ -57,7 +57,7 @@ export default class SetupEncryptionDialog extends React.Component<IProps, IStat
         this.setState({ icon: iconFromPhase(this.store.phase) });
     };
 
-    public render(): JSX.Element {
+    public render(): React.ReactNode {
         return (
             <BaseDialog
                 headerImage={this.state.icon}