Nonpurifiable mutations can still be lost by targeted mutagen

[Venera3]

Describe the bug

Despite setting purifiable: false traits can still be lost by targeted mutagens adding an incompatible trait.

Steps To Reproduce

1. Mutate a non-purifiable trait with mutation incompatibilities (e.g. Proboscis)
2. Choose an incompatible trait(e.g. Wide Mouth) and debug-add it, note that it removes your supposedly-permanent trait
3. Re-add the non-purifiable trait and apply in enough serums of the target category to gain the incompatible trait

Expected behavior

Purifiability being checked in targeted mutations as well.

Screenshots

No response

Versions and configuration

• OS: Windows
  • OS Version: 10.0 2009
• Game Version: 0.F-3890-gda132ebabf-dirty [64-bit]
• Graphics Version: Tiles
• Game Language: English [en]
• Mods loaded: [ Dark Days Ahead [dda], Disable NPC Needs [no_npc_food], No Fungal Growth [no_fungal_growth], Bionic Professions [package_bionic_professions] ]

Additional context

At a glance mutate() - used for non-targeted mutations - checks for purifiability, mutate_towards doesn't.

[anoobindisguise]

oh gosh, just realized this means I won't be able to turn Imperceptive Healer into 8 free points by mutating fast healer. that's scary! I like that certain effects that say they're "permanent" like Ectothermic will actually mean that now, irreversible changes are cool. Especially once mutations will stop being instantaneous now.

[OmniscientQ]

I can confirm this behavior. My post-Threshold slime mutant had Distributed Neurology, and took some Cephalopod serum. The Distributed Neurology was downgraded to "Smart" then upgraded again to "Very Smart".