I did some testing and found a workaround.
Workaround:
1. Be in live mode with your servo and use the cheat traits.remove_trait trait_Humanoid_Robots_MainTrait on the servo (this makes them "human" but they keep their servo skin)
2. Go into CAS, now you can remove things like accessories, shoes, facial hair, and other things that the servo has under their servo skin*
3. Go into live mode again, and use the cheat traits.equip_trait trait_Humanoid_Robots_MainTrait on the servo
*DO NOT remove their servo skin (full body outfit), you won't be able to put it back. I also recommend to not click on the body details category, since this can temporarily remove the servo skin (it comes back either if you click on another category or if you go into live mode), mainly because that breaks the immersion, in case you don't want to know what the servo looks like under the servo skin. Just click on the X on the body details category, if you want to remove the body hair without having to see your servo without their servo skin. To be able to remove head hair, facial hair, makeup and other things on the head you have to first click on the servo's body and then zoom in on the head, it doesn't work to just click on the head directly.
If you do this your servo won't have facial and body hair, which means that they won't have the interactions for facial and body hair (shaving, other sims mocking their facial/body hair, other sims supporting their facial/body hair). By removing all the other things too (except for the servo skin, it's a full body outfit) you also don't have to deal with pack tags if you upload your servos to the gallery.
I tried this with four servos, two of them were built at a robotics workstation and two of them were auto-generated. I haven't found any issues or bugs with this workaround yet. The servos that were built even retained their creator/creation relationship with their creator.
