allow nerfed mobs to jump again

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.

Spigot-Server-Patches/Allow-nerfed-mobs-to-jump.patch

@@ -56,14 +56,14 @@ index 3c48d9463..7b02b253c 100644
          }
          // Spigot End
 diff --git a/src/main/java/net/minecraft/server/PathfinderGoalFloat.java b/src/main/java/net/minecraft/server/PathfinderGoalFloat.java
-index b3b303b3b..fc8be86fd 100644
+index b3b303b3b..fc6c3bf71 100644
 --- a/src/main/java/net/minecraft/server/PathfinderGoalFloat.java
 +++ b/src/main/java/net/minecraft/server/PathfinderGoalFloat.java
 @@ -0,0 +0,0 @@ public class PathfinderGoalFloat extends PathfinderGoal {
  
      public PathfinderGoalFloat(EntityInsentient entityinsentient) {
          this.a = entityinsentient;
-+        if (entityinsentient.fromMobSpawner && entityinsentient.getWorld().paperConfig.nerfedMobsShouldJump) entityinsentient.goalFloat = this; // Paper
++        if (entityinsentient.getWorld().paperConfig.nerfedMobsShouldJump) entityinsentient.goalFloat = this; // Paper
          this.a(4);
          if (entityinsentient.getNavigation() instanceof Navigation) {
              ((Navigation) entityinsentient.getNavigation()).c(true);