Add some way to affect mutation visibility and NPC reactions to it

[Standing-Storm]

Is your feature request related to a problem? Please describe.

While working on #72370, I got it working but it didn't have the desired effect. As you can see in the screenshot in the PR, even with ugliness reduced to 0 by photokinetic illusions, NPCs still ran away from a post-threshold slime mutant and I eventually determined this is because they were checking mutation visibility, which there is no current way to mitigate.

You can check this yourself by making a custom mutation with -99 Ugliness and 99 Visibility. The response of all NPCs who see you is to run screaming in terror.

Solution you would like.

Some way to affect mutation visibility on a whole-body basis--while clothing/visibility interactions should be limb-based, concealing illusions would affect everything.

Describe alternatives you have considered.

No response

Additional context

No response

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. Please do not bump or comment on this issue unless you are actively working on it. Stale issues, and stale issues that are closed are still considered.