Mirroring geometry sometimes multiplies bone folders ( twice Arm-L for example) and shouldn't

[ThomasFrickHytale]

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Gif shows the issue:

Mirroring a piece of R-hand will remake the entire bone hierarchy, dupplicate it, empty, and this creates a lot of problems in the long run.

The expected behavior would be to simply place mirrored Geo into the folder with proper name if it already exists ( L-hand in this case)