Brush shape appears a circle rather than the selected texture.

Steps To Reproduce:

1. Hierarchy -> 3D Object -> Terrain
2. In the inspector go to paint details tab.
3. Select a brush shape other than a circle(Star for example).
4. Hover over the terrain.

Actual Result: Brush shape is a circle.

Expected Result: Brush shape should of the selected shape from the palette.

Reproducible On: 2018.3.0b9, 2018.3.0b6

Not Reproducible In: 2019.1.0a8, 2018.3.0b5

Environment: Win and Mac