Inner planes of potted azaleas are shaded

Discovered while testing MC-262694. Closely relates to MC-129826.

The bug

The inner cross shape of azaleas in flower pots is directionally shaded. Other cross shapes in the game, such as flowers and tall grass, are not shaded, so this may not be intended.

How to fix

The last two elements in template_potted_azalea_bush.json can have

"shade": false

added to them to remove this shading and fix this issue. A model file that implements this fix is attached. Also attached is a model file which uses the optimized pot system described in MC-262433, a bug which I highly recommend fixing because it's incredibly easy to and benefits performance.