Core/Handlers: apply some movement related corrections

Port From (https://github.com/TrinityCore/TrinityCore/commit/476566871879abe51a48833a01cec427dd7c6b8e)

Source/Game/Handlers/PetHandler.cs

@@ -140,8 +140,7 @@ namespace Game
                     switch ((CommandStates)spellid)
                     {
                         case CommandStates.Stay: // flat = 1792  //STAY
-                            pet.StopMoving();
-                            pet.GetMotionMaster().Clear();
+                            pet.GetMotionMaster().Clear(MovementGeneratorPriority.Normal);
                             pet.GetMotionMaster().MoveIdle();
                             charmInfo.SetCommandState(CommandStates.Stay);
 
@@ -183,7 +182,6 @@ namespace Game
                                 if (!owner.IsValidAttackTarget(TargetUnit))
                                     return;
 
-                            pet.ClearUnitState(UnitState.Follow);
                             // This is true if pet has no target or has target but targets differs.
                             if (pet.GetVictim() != TargetUnit || !pet.GetCharmInfo().IsCommandAttack())
                             {
@@ -367,7 +365,6 @@ namespace Game
                             // This is true if pet has no target or has target but targets differs.
                             if (pet.GetVictim() != unit_target)
                             {
-                                pet.GetMotionMaster().Clear();
                                 CreatureAI ai = pet.ToCreature().GetAI();
                                 if (ai != null)
                                 {
@@ -686,7 +683,6 @@ namespace Game
                 return;
 
             SpellCastTargets targets = new(caster, petCastSpell.Cast);
-            caster.ClearUnitState(UnitState.Follow);
 
             Spell spell = new(caster, spellInfo, TriggerCastFlags.None);
             spell.m_fromClient = true;