Double line appears after drawing first two vertices when creating a polygon

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**mapbox-gl-js version**: 1.3.0
**mapbox-gl-draw version**: 1.12.2

### Steps to Trigger Behavior

1. Draw two points on a polygon and move mouse to place the third point

### Expected Behavior
Only one line should appear connecting the first and second polygon vertices.

### Actual Behavior
The DrawLine and first polygon line appear between the first and second vertices and overlap which looks messy. I would like the DrawLine to only show before we place the second point. If I remove the drawline all together then no line is show when I am placing the second point.

Before click:

After click:

Styling:

` {
id: 'gl-draw-polygon-stroke-active',
type: 'line',
filter: ['all', ['==', 'active', 'true'], ['==', '$type', 'Polygon']],
layout: {
'line-cap': 'round',
'line-join': 'round',
},
paint: {
'line-color': polygonColorFormula,
'line-dasharray': [0.2, 2],
'line-width': 2,
},
},

{
id: 'gl-draw-line-active',
type: 'line',
filter: ['all', ['==', '$type', 'LineString'], ['==', 'active', 'true']],
layout: {
'line-cap': 'round',
'line-join': 'round',
},
paint: {
'line-color': polygonColorFormula,
'line-dasharray': [0.2, 2],
'line-width': 2,
'line-opacity': lineOpacity,
},
},`

Reproduce the behavior using mapbox-gl-js 1.3.0 and mapbox-gl-draw 1.12.2 by placing two polygon points and moving the mouse. Start by examining the gl-draw-polygon-stroke-active and gl-draw-line-active styles shown in the issue. Done means only one line is visible between the first two vertices while placing the third point.

Written by the indexing model from the issue text.