[MM-54798] Convert ./components/widgets/separator/basic-separator.tsx to function component (#24788)

* chore(channels): convert basic separator to functional components

* chore: change to arrow function

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/widgets/separator/basic-separator.tsx

@@ -9,9 +9,7 @@ type Props = {
     children?: ReactNode;
 };
 
-export default class BasicSeparator extends React.PureComponent<Props> {
+const BasicSeparator = ({children}: Props) => {
-    public render() {
-        const {children} = this.props;
     return (
         <div
             data-testid='basicSeparator'
@@ -25,5 +23,6 @@ export default class BasicSeparator extends React.PureComponent<Props> {
             )}
         </div>
     );
-    }
+};
-}
+
+export default React.memo(BasicSeparator);