fix(Scripts/RazorfenDowns): prevent Belnistrasz evade during channeling (#25431)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/server/scripts/Kalimdor/RazorfenDowns/razorfen_downs.cpp

@@ -100,6 +100,16 @@ public:
             }
         }
 
+        void JustExitedCombat() override
+        {
+            if (channeling)
+            {
+                EngagementOver();
+                return;
+            }
+            CreatureAI::JustExitedCombat();
+        }
+
         void JustEngagedWith(Unit* who) override
         {
             if (channeling)