Fix several Exit End Portal related bugs

[XXMA16]

Added fixes for the following issues (macro view):

• potion effects not being ported over when using the Exit End Portal
• body part health not being ported when using the Exit End Portal (FirstAid)
• losing some health when joining a world (FirstAid)

The actual issues stem from the very weird way Minecraft handles the End Exit and FirstAid, ScalingHaalth and PotionCore not accounting for this.

I have done some testing and it seems the player won't randomly die when exiting the end and doesn't get extra health.

Some issues still persist:

• body part health distribution is non-deterministic when using baubles with health boosting modifiers
• baubles with health modifiers still cause the player to lose some hp when returning from the End
• slight client desync when returning from the End (FirstAid health overlay, will sync up)