Model of Stone Brick Stairs slightly changes depending on view

Found while testing MCPE-31021 (which can also be seen here).

The Stone Brick Stairs block changes slightly depending on the direction it is looked at from. When looked at straight on, the pixels are parallel, but looking down slightly causes these lines to suddenly converge.

To reproduce:

• Place two Stone Brick Stairs blocks at eye level

• Stare at them straight on

• Move the camera down slightly