Prevent draggable marker touch event propagation

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**mapbox-gl-js version**: v1.9.0

### Question

I'm using Mapbox in a Facebook Messenger chatbot which renders the map inside an HTML webview. When dragging a draggable marker, the `touchmove` event also gets propagated to the parent webview. This then moves it up and down. I can't immediately see a way to get the event in the drag handlers so that I could call `event. stopPropagation()`.

Here's an example of the issue:


Is there an accepted method to achieve this?
Can I get access to the events in the drag handlers or is there a better way to do this?

Thanks!

### Links to related documentation

https://docs.mapbox.com/mapbox-gl-js/api/markers/#marker-events

Start with the Marker events documentation linked in the issue and trace the draggable marker touch and drag handlers. Reproduce the touchmove propagation in the Messenger webview, then verify that dragging a marker no longer moves the parent webview without breaking marker dragging.

Written by the indexing model from the issue text.