MapMouseEvent misses lngLat property on drag

@mourner is already working on this.

Since Jul 9, 2021.

**browser**:
Chrome@72.0

### Steps to Trigger Behavior

1.Listento drag Event
2. Try access Latlng property from MapMouseEvent
3.

### Link to Demonstration

[demonstration](https://jsbin.com/tizemukuna/edit?html,console,output )
```

Display a map

body { margin:0; padding:0; }
#map { position:absolute; top:0; bottom:0; width:100%; }

mapboxgl.accessToken = 'pk.eyJ1IjoibWFwYm94IiwiYSI6ImNpejY4M29iazA2Z2gycXA4N2pmbDZmangifQ.-g_vE53SD2WrJ6tFX7QHmA';
var map = new mapboxgl.Map({
container: 'map', // container id
style: 'mapbox://styles/mapbox/streets-v9', // stylesheet location
center: [-74.50, 40], // starting position [lng, lat]
zoom: 9 // starting zoom
});

map.on('drag', function(e){
console.log(e)
});

```

### Expected Behavior
According to the [docs](https://docs.mapbox.com/mapbox-gl-js/api/#mapmouseevent)
the MapMouseEvent Object should contain following properties:
- type
- target
- originalEvent
- point
- lngLat
- preventDefault()
- defaultPrevented
### Actual Behavior
- type
- originalEvent
- target
**accessing lngLat would result in** `undefined`