[Glitch] Update to Twemoji 15.1.0

Port e96044f389 to glitch-soc

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

app/javascript/flavours/glitch/features/compose/components/emoji_picker_dropdown.jsx

@@ -41,7 +41,7 @@ let EmojiPicker, Emoji; // load asynchronously
 
 const listenerOptions = supportsPassiveEvents ? { passive: true, capture: true } : true;
 
-const backgroundImageFn = () => `${assetHost}/emoji/sheet_15.png`;
+const backgroundImageFn = () => `${assetHost}/emoji/sheet_15_1.png`;
 
 const notFoundFn = () => (
   <div className='emoji-mart-no-results'>