Fix settings page showing all tabs on first load

Non-active tab groups were visible during async data loading because
switchSettingsTab ran after the awaits. Moved it before async calls and
added CSS defaults to hide non-connections groups, preventing any flash.

webui/static/script.js

@@ -3040,11 +3040,11 @@ async function loadPageData(pageId) {
                 break;
             case 'settings':
                 initializeSettings();
+                switchSettingsTab('connections');
                 await loadSettingsData();
                 await loadQualityProfile();
                 loadApiKeys();
                 loadBlacklistCount();
-                switchSettingsTab('connections');
                 break;
             case 'stats':
                 initializeStatsPage();