Fix holograms

[Beaness]

Fixes 2 things:

• Entity metadata is now saved. The issue was that if a new entity data packet is send without the flags being changed the state isn't correctly calculated.
• Zombie no gravity now has a more correct offset (fix on top of Add support for armor stands with no gravity as zombie #609)
• Interactions on 1.7 are improved by also accounting for "extra" entity ids (the riding entity) as an interactable entity

[florianreuth]

Could you maybe add me on my new discord account again: florianreuth? I'll take a look at your PRs some time soon, but have some other things to do atm

[florianreuth]

I'm not too familiar with the hologram emulation code anymore, but overall this looks good. Would merge otherwise.