Make shadow cascade debug colors match editor UI colors.

[arttu-peltonen]

Purpose of this PR

Making sure Shadow Cascade debug colors in the viewport match the ones in the editor UI. The colors are not 100% the same in order to have better contrast in the viewport under varying lighting conditions.

URP before:

URP after:

HDRP before:

HDRP after:

Also fixed apparent typo resulting in too bright color in the UI:
before:

after:

---

Testing status

Checked URP & HDRP look as expected.

[github-actions]

Hi! This comment will help you figure out which jobs to run before merging your PR. The suggestions are dynamic based on what files you have changed.
Link to Yamato: https://yamato.cds.internal.unity3d.com/jobs/902-Graphics
Search for your PR branch using the sidebar on the left, then add the following segment(s) to the end of the URL (you may need multiple tabs depending on how many packages you change)

HDRP
/.yamato%252Fall-hdrp.yml%2523PR_HDRP_2021.2

URP
/.yamato%252Fall-urp.yml%2523PR_URP_2021.2

SRP Core
You could run ABV on your branch before merging your PR, but it will start A LOT of jobs. Please be responsible about it and run it only when you feel the PR is ready:
/.yamato%252F_abv.yml%2523all_project_ci_2021.2
Be aware that any modifications to the Core package impacts everyone in the Graphics repo so please discuss the PR with your lead.

Depending on the scope of your PR, you may need to run more jobs than what has been suggested. Please speak to your lead or a Graphics SDET (#devs-graphics-automation) if you are unsure.

[nigeljw-unity]

LGTM

[sebastienlagarde]

good catch, thanks

[erikabar]

Developer already tested this in URP and HDRP, approving without additional testing

[arttu-peltonen]

Yamato against 21.2 is broken, so running PR jobs against latest green (cb3b74b20e592145e75fb03993f7a23e2c09e03a) now.

EDIT: rerunning jobs after Yamato is back up and HDRP test images are fixed:
HDRP https://unity-ci.cds.internal.unity3d.com/job/8394457
URP https://unity-ci.cds.internal.unity3d.com/job/8394595

[arttu-peltonen]

@sebastienlagarde this should be good to go. Fixed HDRP test images for a test that used cascade debug mode, URP doesn't have a corresponding test. Failures in both test suites but couldn't spot anything that would seem related.

[RSlysz]

Nice catch for the typo. It should be me, sorry.