Flashing lights in volumetric fog when attenuation is above 3

### Tested versions

- Reproducible in 4.2 and 4.2.1

### System information

Godot v4.2.1.stable - Windows 10.0.22631 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 960 (NVIDIA; 31.0.15.4617) - Intel(R) Core(TM) i5-10400F CPU @ 2.90GHz (12 Threads)

### Issue description

Lights with a high attenuation flicker when placed in a volumetric fog (effect appears both in scene view and when I run the project).
The effect seem to change randomly depending on the distance to the point of view.
Here the attenuations are 1;3;4 in order for those three lights.

https://github.com/godotengine/godot/assets/12957658/6989158b-ab6e-4863-bfe2-9bc612f022bd

### Steps to reproduce

- Create a scene 3d
- create a WorldEnvironment and activate volumetric fog
- create an omnilight and increase it's attenuation above 3
- (optional) move the light relative to the point of view, it makes the effect more noticeable

### Minimal reproduction project (MRP)

[LightsFlashInVolFogMRP.zip](https://github.com/godotengine/godot/files/14051497/LightsFlashInVolFogMRP.zip)

Start by opening the attached LightsFlashInVolFogMRP.zip and reproduce the issue in Godot 4.2.1 with Vulkan, volumetric fog, and an OmniLight attenuation above 3. Compare scene and running-project behavior while changing the light's distance from the viewpoint. Done means the light no longer flickers across those viewpoints and the reproduction steps remain stable.

Written by the indexing model from the issue text.