[Glitch] Fix media gallery items having incorrect borders when hidden

Port 51769e0670 to glitch-soc

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

app/javascript/flavours/glitch/components/media_gallery.jsx

@@ -356,14 +356,14 @@ class MediaGallery extends PureComponent {
 
     return (
       <div className={computedClass} style={style} ref={this.handleRef}>
+        {children}
+
         {(!visible || uncached) && (
           <div className={classNames('spoiler-button', { 'spoiler-button--click-thru': uncached })}>
             {spoilerButton}
           </div>
         )}
 
-        {children}
-
         {(visible && !uncached) && (
           <div className='media-gallery__actions'>
             <button className='media-gallery__actions__pill' onClick={this.handleOpen}><FormattedMessage id='media_gallery.hide' defaultMessage='Hide' /></button>