Core/Packets: Reduce memory footprint of cached queries (#22297)

Ensure only the minimum required memory is used by caching query packets by calling shrink_to_fit()

src/server/shared/Packets/ByteBuffer.h

@@ -413,6 +413,11 @@ class TC_SHARED_API ByteBuffer
                 _storage.reserve(ressize);
         }
 
+        void shrink_to_fit()
+        {
+            _storage.shrink_to_fit();
+        }
+
         void append(const char *src, size_t cnt)
         {
             return append((const uint8 *)src, cnt);