Bees try to get pollen from wither flowers.

Put the summary of the bug you're having here

What I expected to happen was...:
I feel bees should not try to get wither flower pollen or just make a special poisonous honey.

What actually happened was...:
Bees try to get wither flower's pollen and die.

Steps to Reproduce:
1. Find or spawn a bee hive
2. Place wither flowers
3. Spawn or wait for bees