Handle Plugin Center Authentication failures (#1940)

If the plugin center authentication fails,
the plugins are fetched without authentication
and a warning is displayed on the plugin page.

Co-authored-by: Konstantin Schaper <konstantin.schaper@cloudogu.com>

scm-ui/ui-components/src/SmallLoadingSpinner.tsx

@@ -22,13 +22,16 @@
  * SOFTWARE.
  */
 import React, { FC } from "react";
+import classNames from "classnames";
 
-const SmallLoadingSpinner: FC = () => {
-  return (
-    <div className="loader-wrapper">
-      <div className="loader is-loading" />
-    </div>
-  );
+type Props = {
+  className?: string;
 };
 
+const SmallLoadingSpinner: FC<Props> = ({ className }) => (
+  <div className={classNames("loader-wrapper", className)}>
+    <div className="loader is-loading" />
+  </div>
+);
+
 export default SmallLoadingSpinner;