Template expression for switching on whether the template is rendered as a preview

Instead of using listmonks built-in tracking, I'm using a [Umami]( for tracking. So in my template, I'm removing the {{ TrackView }} and adding my own pixel. However, this also means that any time the editor preview is used, this also counts as a view.

Instead, it was nice if there was a template expression to distinguish between whether the template is being rendered in a preview or the actual outgoing email so the pixel can be added conditionally.