Load Issue Sidebar Data through startup.js

app/assets/javascripts/lib/utils/axios_startup_calls.js

@@ -33,6 +33,9 @@ const setupAxiosStartupCalls = axios => {
             fetchHeaders[key] = val;
           });
 
+          // We can delete it as it anyhow should only be called once
+          delete startupCalls[fullUrl];
+
           // eslint-disable-next-line promise/no-nesting
           return res
             .clone()

app/views/shared/issuable/_sidebar.html.haml

@@ -4,6 +4,7 @@
 - issuable_type = issuable_sidebar[:type]
 - signed_in = !!issuable_sidebar.dig(:current_user, :id)
 - can_edit_issuable = issuable_sidebar.dig(:current_user, :can_edit)
+- add_page_startup_api_call "#{issuable_sidebar[:issuable_json_path]}?serializer=sidebar_extras"
 
 - if Feature.enabled?(:vue_issuable_sidebar, @project.group)
   %aside#js-vue-issuable-sidebar{ data: { signed_in: signed_in,