MM-56010: changed accordion_toggle_icon.tsx to functional component (#25651)

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

webapp/channels/src/components/widgets/icons/accordion_toggle_icon.tsx

@@ -3,10 +3,11 @@
 
 import React from 'react';
 
-export default class AccordionToggleIcon extends React.PureComponent<React.HTMLAttributes<HTMLSpanElement>> {
-    render(): JSX.Element {
+export default function AccordionToggleIcon(
+    props: React.HTMLAttributes<HTMLSpanElement>,
+) {
     return (
-            <span {...this.props}>
+        <span {...props}>
             <svg
                 width='30px'
                 height='30px'
@@ -56,4 +57,3 @@ export default class AccordionToggleIcon extends React.PureComponent<React.HTMLA
         </span>
     );
 }
-}