Entity AI tasks are initialized earlier in recent versions
of MC, this means that the fromMobSpawner has not been set
at the point where AI tasks are initilazed and so the goalFloat
will never be populated.
To rectify this, we can rely on the entity tick checking if
the mob is from a spawner each tick, and just initialize the
field should the paper option be enabled. This saves us from
having to modify the call chain in order to pass the fact that
it was created by a mobSpawner earlier.
Use -1 to represent vanilla/unlimited.
Updated PaperWorldConfig to also update the individual worlds limit if it was set
to the new default value.
Should hopefully help #235
