Give silicons proper lobby/character editor previews (#33763)

Give silicons proper lobby/character editor previews (#33763)

* Give silicons proper lobby/character editor previews

No more naked dummies, properly show a borg/AI sprite now.

This means taking the JobEntity into account when spawning the dummy. For AIs I had to add a "JobPreviewEntity" field because they'd look like a posibrain otherwise. AI therefore uses a custom dummy entity I defined.

Also I had to add some margins to the UI, because otherwise the 32x32 sprite of the AI would look bad.

* Update Content.Shared/Roles/JobPrototype.cs

* Update Content.Client/Lobby/LobbyUIController.cs

* Update Resources/Prototypes/Entities/Mobs/Player/silicon.yml

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Co-authored-by: slarticodefast <161409025+slarticodefast@users.noreply.github.com>