[Glitch] Ensure tabIndex is number instead of string

Port ec0c104bf2 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/features/notifications/components/follow_request.jsx

@@ -95,7 +95,7 @@ class FollowRequest extends ImmutablePureComponent {
 
     return (
       <HotKeys handlers={this.getHandlers()}>
-        <div className={classNames('notification notification-follow-request focusable', { unread })} tabIndex='0'>
+        <div className={classNames('notification notification-follow-request focusable', { unread })} tabIndex={0}>
           <div className='notification__message'>
             <div className='notification__favourite-icon-wrapper'>
               <Icon id='user' fixedWidth />