chore: add missing include in EntityAPI.cpp

Author: ShrBox

src/legacy/api/EntityAPI.cpp

@@ -39,6 +39,7 @@
 #include "mc/world/actor/provider/ActorEquipment.h"
 #include "mc/world/actor/provider/SynchedActorDataAccess.h"
 #include "mc/world/attribute/Attribute.h"
+#include "mc/world/attribute/AttributeInstance.h" // IWYU pragma: keep
 #include "mc/world/attribute/AttributeInstanceHandle.h" // IWYU pragma: keep
 #include "mc/world/attribute/SharedAttributes.h"
 #include "mc/world/effect/EffectDuration.h"