Update relevant meta message lines on named asset.

Otherwise, if you switch category and the new asset layer is added
before the old is removed, the old (still visible) layer asset found
would fire but change the meta message of the new layer.

CHANGELOG.md

@@ -29,6 +29,7 @@
         - Improve moderation diff display in a few small ways. #3105
         - Do not have bootstrap run sudo commands. #2930
         - Fix lookups in templates of categories with &s.
+        - Fix a few obscure asset layer changing issues.
     - Admin improvements:
         - Display user name/email for contributed as reports. #2990
         - Interface for enabling anonymous reports for certain categories. #2989

web/cobrands/fixmystreet/assets.js

@@ -883,7 +883,7 @@ fixmystreet.assets = {
         if (!message) {
             message = get_asset_pick_message.call(this);
         }
-        $('.category_meta_message').html(message);
+        update_message_display.call(this, message);
     },
     named_select_action_not_found: function() {
         var message = get_asset_pick_message.call(this);