[MM-57712] Convert ./components/post_deleted_modal.tsx from Class Component to Function Component (#26731)

* [MM-57712] Convert `./components/post_deleted_modal.tsx` from Class Component to Function Component

* 🎨 Improve code quality

---------

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

webapp/channels/src/components/post_deleted_modal.tsx

@@ -1,7 +1,7 @@
 // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
 // See LICENSE.txt for license information.
 
-import React from 'react';
+import React, {useState, memo, useCallback} from 'react';
 import {Modal} from 'react-bootstrap';
 import {FormattedMessage} from 'react-intl';
 
@@ -9,30 +9,19 @@ type Props = {
     onExited: () => void;
 }
 
-type State = {
-    show: boolean;
-}
+const PostDeletedModal = ({
+    onExited,
+}: Props) => {
+    const [show, setShow] = useState(true);
 
-export default class PostDeletedModal extends React.PureComponent<Props, State> {
-    constructor(props: Props) {
-        super(props);
+    const handleHide = useCallback(() => setShow(false), []);
 
-        this.state = {
-            show: true,
-        };
-    }
-
-    private handleHide = () => {
-        this.setState({show: false});
-    };
-
-    public render(): JSX.Element {
     return (
         <Modal
             dialogClassName='a11y__modal'
-                show={this.state.show}
-                onHide={this.handleHide}
-                onExited={this.props.onExited}
+            show={show}
+            onHide={handleHide}
+            onExited={onExited}
             role='dialog'
             aria-labelledby='postDeletedModalLabel'
             data-testid='postDeletedModal'
@@ -61,7 +50,7 @@ export default class PostDeletedModal extends React.PureComponent<Props, State>
                     type='button'
                     className='btn btn-primary'
                     autoFocus={true}
-                        onClick={this.handleHide}
+                    onClick={handleHide}
                     data-testid='postDeletedModalOkButton'
                 >
                     <FormattedMessage
@@ -72,5 +61,6 @@ export default class PostDeletedModal extends React.PureComponent<Props, State>
             </Modal.Footer>
         </Modal>
     );
-    }
-}
+};
+
+export default memo(PostDeletedModal);