update (core): Knock Back Helpers (#12639)

Adds knock back helpers to the core for future core and module use.

src/server/game/Entities/Player/Player.cpp

@@ -222,6 +222,7 @@ Player::Player(WorldSession* session): Unit(true), m_mover(this)
     m_bHasDelayedTeleport = false;
     teleportStore_options = 0;
     m_canTeleport = false;
+    m_canKnockback = false;
 
     m_trade = nullptr;
 

src/server/game/Entities/Player/Player.h

@@ -2430,6 +2430,8 @@ class Player : public Unit, public GridObject<Player>
 
     bool CanTeleport() { return m_canTeleport; }
     void SetCanTeleport(bool value) { m_canTeleport = value; }
+    bool CanKnockback() { return m_canKnockback; }
+    void SetCanKnockback(bool value) { m_canKnockback = value; }
 
     bool isAllowedToLoot(Creature const* creature);
 
@@ -2883,6 +2885,7 @@ class Player : public Unit, public GridObject<Player>
     bool m_bMustDelayTeleport;
     bool m_bHasDelayedTeleport;
     bool m_canTeleport;
+    bool m_canKnockback;
 
     std::unique_ptr<PetStable> m_petStable;
 

src/server/game/Entities/Unit/Unit.cpp

@@ -18727,6 +18727,7 @@ void Unit::KnockbackFrom(float x, float y, float speedXY, float speedZ)
             player->SetCanFly(true, true);
 
         sScriptMgr->AnticheatSetSkipOnePacketForASH(player, true);
+        player->SetCanKnockback(true);
     }
 }