Reinforced Deepslate can be destroyed by the wither

Summary:
Reinforced Deepslate can be destroyed by the wither. This breaks parity with Java versions.

Steps to reproduce:

1. Place Reinforced Deepslate.
2. Summon the wither.

Observed results:
Wither explosion destroys Reinforced Deepslate.

Expected results:
Wither explosion will not destroy Reinforced Deepslate.