Screenspace Denoiser creates artifacts for Ray Traced Shadows

1. Screen space denoiser creates two types of artifacts:
   1. artifacts around boundary for general lighting

The artifact is there before 5.2 but since the ray traced shadow denoiser denoises on the sqr() space previously, that artifact is less noticeable. After bug fix in 5.2, we get better shadows but also reveals this artifact. Need to improve the ray traced shadow denoiser to reduce this artifacts.

Occurs in both 5.3.1 and 5.3.2, this is not a regression. Tested in //UE5/Release-5.3 @ CL29314046

1. Open the project attached
2. Pilot the camera
3. Select the Directional Light
4. Change the Source Angle to 0
5. Change the Source Angle to 1
6. Change the Source Angle to 5
7. Notice the artifacting near the cube's edge

Results: Artifacts can be seen from the edge of the cube overlapping with the shadow
Expected: No artifacts occur on the edge of the cube