Display non-post embeds in composer preview (#5647)

* Display non-post embeds in composer preview

* Remove starter pack special case from ExternalLinkEmbed

This should not be needed because starter pack composer preview now goes through the record preview codepath, just like in the feed/post view.

* Hide record ext links if quote is present

* Align remove buttons

Remove the implicit top padding in record embeds and make it conditional, which is similar to how we treat external link embeds. This makes the X button appear in the same place for record embeds as with links.

src/components/StarterPack/StarterPackCard.tsx

@@ -141,7 +141,6 @@ export function Embed({
   return (
     <View
       style={[
-        a.mt_xs,
         a.border,
         a.rounded_sm,
         a.overflow_hidden,