`embeddableFlow.mount(cssSelectorOrDomElement)`

mount adds the EmbeddableFlow to the DOM. It takes a single argument that can be either
a valid CSS selector or a DOM element. Note that:

If a CSS selector matches multiple DOM elements, then the flow will be added to the first matching element.
If the flow is already mounted, this method will do nothing.
Void HTML elements cannot have children, so cannot be mounted to.

<div id="mount-here"> </div>

<script>
  const embeddableFlow = mt.createEmbeddableFlow({ clientToken: "..." });
  embeddableFlow.mount("#mount-here")
</script>

<div id="mount-here"> </div>

<script>
  const embeddableFlow = mt.createEmbeddableFlow({ clientToken: "..." });
  const element = document.querySelector("#mount-here")
  
  embeddableFlow.mount(element)
</script>