Boss darkened ambient light is too reddish

The darkening effect applied by the Wither boss is way too red when compared to older versions.

Steps to Reproduce:

1. Summon the Wither on version 1.21.8 or older

2. Summon the Wither on version 1.21.9 or newer

3. Compare the colors

Observed Results:
The environment tint is very noticeably reddish.

Expected Results:
The environment tint is subtler, matching older versions.