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 &&