Enable GTM Built-in Variables

ENABLES GTM built-in variables (Click URL, Form ID, Scroll Depth, Video Percent, Page Path…). These are OFF by default, and a trigger/tag that references a disabled built-in variable silently never fires; this is the usual cause of click/scroll/form triggers not working. types = comma-separated built-in variable names (clickUrl, clickClasses, formId, scrollDepthThreshold, videoPercent…). Common: pageUrl,pageHostname,pagePath,referrer,clickElement,clickClasses,clickId,clickTarget,clickUrl,clickText,formElement,formClasses,formId,formTarget,formUrl,formText,scrollDepthThreshold,scrollDepthUnits,scrollDirection,videoProvider,videoStatus,videoUrl,videoTitle,videoPercent,videoDuration,videoCurrentTime,errorMessage,errorUrl,errorLine,historySource,newHistoryFragment,oldHistoryFragment. confirm=false previews. Publish afterwards with publish_gtm_container.