Add aggressive mob API (#9838)

patches/api/Missing-Entity-API.patch

@@ -633,6 +633,49 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     */
 +    @org.jetbrains.annotations.Nullable
 +    Llama getCaravanTail();
++    // Paper end
+ }
+diff --git a/src/main/java/org/bukkit/entity/Mob.java b/src/main/java/org/bukkit/entity/Mob.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/entity/Mob.java
++++ b/src/main/java/org/bukkit/entity/Mob.java
+@@ -0,0 +0,0 @@ public interface Mob extends LivingEntity, Lootable {
+      */
+     @Nullable
+     public Sound getAmbientSound();
++
++    // Paper start
++    /**
++     * Some mobs will raise their arm(s) when aggressive:
++     * <ul>
++     *     <li>{@link Drowned}</li>
++     *     <li>{@link Piglin}</li>
++     *     <li>{@link Skeleton}</li>
++     *     <li>{@link Zombie}</li>
++     *     <li>{@link ZombieVillager}</li>
++     *     <li>{@link Illusioner}</li>
++     *     <li>{@link Vindicator}</li>
++     *     <li>{@link Panda}</li>
++     *     <li>{@link Pillager}</li>
++     *     <li>{@link PiglinBrute}</li>
++     * </ul>
++     * <p>
++     * Note: This doesn't always show the actual aggressive state as
++     * set by {@link #setAggressive(boolean)}. {@link Panda}'s are always
++     * aggressive if their combined {@link Panda.Gene} is {@link Panda.Gene#AGGRESSIVE}.
++     *
++     * @return wether the mob is aggressive or not
++     */
++    boolean isAggressive();
++
++    /**
++     * Some mobs will raise their arm(s) when aggressive,
++     * see {@link #isAggressive()} for full list.
++     *
++     * @param aggressive wether the mob should be aggressive or not
++     * @see #isAggressive()
++     */
++    void setAggressive(boolean aggressive);
 +    // Paper end
  }
 diff --git a/src/main/java/org/bukkit/entity/MushroomCow.java b/src/main/java/org/bukkit/entity/MushroomCow.java