Revert "Upgrade new Web Share Target API (mastodon#9963)"

This reverts commit b253d3e.

Author: masanbol

app/serializers/manifest_serializer.rb

@@ -52,14 +52,6 @@ def scope
   end
 
   def share_target
-    {
-      url_template: 'share?title={title}&text={text}&url={url}',
-      action: 'share',
-      params: {
-        title: 'title',
-        text: 'text',
-        url: 'url',
-      },
-    }
+    { url_template: 'share?title={title}&text={text}&url={url}' }
   end
 end