fix: Fixes double calls with Target cancel and spell sequences (#1840)

### Summary
- Cleans up target cancellation being called incorrectly.
- An invalid target type (which should never happen), now calls `OnTargetUntargetable` instead of `OnTargetCanceled`
- Removes double calls to `FinishSequence` in Spells.

Projects/UOContent/Spells/Third/Bless.cs

@@ -40,8 +40,6 @@ namespace Server.Spells.Third
 
                 BuffInfo.AddBuff(m, new BuffInfo(BuffIcon.Bless, 1075847, 1075848, length, m, args));
             }
-
-            FinishSequence();
         }
 
         public override bool CheckCast()

Projects/UOContent/Spells/Third/Fireball.cs

@@ -55,8 +55,6 @@ namespace Server.Spells.Third
 
                 SpellHelper.Damage(this, m, damage, 0, 100, 0, 0, 0);
             }
-
-            FinishSequence();
         }
 
         public override void OnCast()

Projects/UOContent/Spells/Third/MagicLock.cs

@@ -58,8 +58,6 @@ namespace Server.Spells.Third
                 cont.LockLevel = ILockpickable.MagicLock; // signal magic lock
                 cont.Locked = true;
             }
-
-            FinishSequence();
         }
 
         public override void OnCast()

Projects/UOContent/Spells/Third/Poison.cs

@@ -95,8 +95,6 @@ namespace Server.Spells.Third
 
                 HarmfulSpell(m);
             }
-
-            FinishSequence();
         }
 
         public override void OnCast()

Projects/UOContent/Spells/Third/Telekinesis.cs

@@ -68,8 +68,6 @@ namespace Server.Spells.Third
                     }
                 }
             }
-
-            FinishSequence();
         }
 
         public override void OnCast()

Projects/UOContent/Spells/Third/Teleport.cs

@@ -112,8 +112,6 @@ namespace Server.Spells.Third
                     queue.Dequeue().OnMoveOver(m);
                 }
             }
-
-            FinishSequence();
         }
 
         public override bool CheckCast()

Projects/UOContent/Spells/Third/Unlock.cs

@@ -80,8 +80,6 @@ namespace Server.Spells.Third
                     }
                 }
             }
-
-            FinishSequence();
         }
 
         public override void OnCast()

Projects/UOContent/Spells/Third/WallOfStone.cs

@@ -42,22 +42,16 @@ public class WallOfStoneSpell : MagerySpell, ISpellTargetingPoint3D
                 var targetLoc = new Point3D(eastToWest ? p.X + i : p.X, eastToWest ? p.Y : p.Y + i, p.Z);
                 var canFit = SpellHelper.AdjustField(ref targetLoc, Caster.Map, 22, true);
 
-                // Effects.SendLocationParticles( EffectItem.Create( loc, Caster.Map, EffectItem.DefaultDuration ), 0x376A, 9, 10, 5025 );
-
                 if (!canFit)
                 {
                     continue;
                 }
 
-                Item item = new WallOfStone(targetLoc, Caster.Map, Caster);
+                var item = new WallOfStone(targetLoc, Caster.Map, Caster);
 
                 Effects.SendLocationParticles(item, 0x376A, 9, 10, 5025);
-
-                // new WallOfStone( loc, Caster.Map, Caster );
             }
         }
-
-        FinishSequence();
     }
 
     public override void OnCast()