Fixed zoomed stickers panel

Closes #968

app/less/app.less

@@ -2581,7 +2581,8 @@ img.img_fullsize {
 }
 .composer_emoji_tooltip_tabs_contents {
   position: absolute;
-  width: 200%;
+  // width: 200%;
+  width: 568px;
   .transform(translate3d(0,0,0));
 
   transition: transform ease-in-out 0.2s;