Add alt text support and rework image layout (#503)

* Add alt text support and rework image layout

* Add additional BottomSheet implementation to account for nested Composer modal

* Use mobile gallery layout on mobile web

* Missing key

* Fix lint

* Move altimage modal into the standard modal system

* Fix overflow wrapping of images

* Fixes to the alt-image modal

* Remove unnecessary switch

* Restore old imagelayoutgrid code

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/view/com/notifications/FeedItem.tsx

@@ -369,10 +369,7 @@ function AdditionalPostText({
     <>
       {text?.length > 0 && <Text style={pal.textLight}>{text}</Text>}
       {images && images?.length > 0 && (
-        <ImageHorzList
-          uris={images?.map(img => img.thumb)}
-          style={styles.additionalPostImages}
-        />
+        <ImageHorzList images={images} style={styles.additionalPostImages} />
       )}
     </>
   )