Focus the correct status in media modal

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

app/soapbox/features/status/components/thread.tsx

@@ -122,6 +122,9 @@ const Thread = (props: IThread) => {
     };
   });
 
+  let initialTopMostItemIndex = ancestorsIds.size;
+  if (!useWindowScroll && initialTopMostItemIndex !== 0) initialTopMostItemIndex = ancestorsIds.size + 1;
+
   const [showMedia, setShowMedia] = useState<boolean>(status?.visibility === 'self' ? false : defaultMediaVisibility(status, displayMedia));
 
   const node = useRef<HTMLDivElement>(null);
@@ -407,7 +410,7 @@ const Thread = (props: IThread) => {
 
   if (!useWindowScroll) {
     // Add padding to the top of the Thread (for Media Modal)
-    children.push(<div className='h-4' />);
+    children.push(<div key='padding' className='h-4' />);
   }
 
   if (hasAncestors) {
@@ -444,7 +447,7 @@ const Thread = (props: IThread) => {
           hasMore={!!next}
           onLoadMore={handleLoadMore}
           placeholderComponent={() => <PlaceholderStatus variant='slim' />}
-          initialTopMostItemIndex={ancestorsIds.size}
+          initialTopMostItemIndex={initialTopMostItemIndex}
           useWindowScroll={useWindowScroll}
           itemClassName={itemClassName}
           className={