styling fixes for SteamSpinner

frontend/src/components/settings/pages/testing/index.tsx

@@ -58,7 +58,7 @@ export default function TestingVersionList() {
   if (loading) {
     return (
       <>
-        <SteamSpinner>{t('Testing.loading')}</SteamSpinner>
+        <SteamSpinner background="transparent">{t('Testing.loading')}</SteamSpinner>
       </>
     );
   }

frontend/src/components/store/Store.tsx

@@ -222,7 +222,7 @@ const BrowseTab: FC<{ setPluginCount: Dispatch<SetStateAction<number | null>> }>
       <div>
         {!pluginList ? (
           <div style={{ height: '100%' }}>
-            <SteamSpinner />
+            <SteamSpinner background="transparent" />
           </div>
         ) : (
           pluginList