Feature request: optionally keeping the previous chunkMask when patching a mesh component in an appearanceDefinition

[BrutalBuzzler]

It would be useful when patching/replacing a mesh component to optionally keep/copy the chunkMask from the previous component.

The use case here is e.g. patching the body mesh of an NPC with a character-specific mesh to keep the appearanceDefinitions compatible with typical NPC clothing/appearance changes. This would only work if you could copy the chunk mask from the previous appearance.

Since there is no useful way to determine whether or not this mode should become active and not break existing mods, it seems useful if this patching mode would only activate with a parameter in the .xl file. (I can't think of a better way anyway)