Distant Shadow Splits have Wrong Bias

[mrjustaguy]

Tested versions

since #68339

System information

Vulkan

Issue description

#48776 and #68339 Modify Blur and Bias respectively, but the latter adjusts bias based on the non modified blur value and doesn't take blur modification that the first PR is doing inside the shader.

The bias modification code should be applied to the modified - Final blur values, not the base blur.

Steps to reproduce

Observe Distant Splits bias increase as blur levels increase, without blending splits, and observe how blur levels are the same for the splits, but the bias still increases for those distant splits

Minimal reproduction project (MRP)

N/A

[Calinou]

Note that decreasing bias for distant splits is not always desired. If you do so, you may end up with misaligned splits, which is usually far more noticeable in motion than slight peter-panning in the distance.

#60178 is designed in a way that the perceptual bias does not change according to the shadow distance, so that long lines of shadows remain straight lines.

See the screenshots I added to OP in #60178.

[mrjustaguy]

This is Normal Bias doing this, this doesn't affect regular Bias that is the issue here.