Core/Units: Cleanup hardcoded magic numbers for byte field offsets

(cherry picked from commit ac1dc75)

src/server/scripts/Spells/spell_generic.cpp

@@ -3809,7 +3809,7 @@ public:
             if (!target)
                 return;
 
-            target->SetByteValue(UNIT_FIELD_BYTES_1, 0, UNIT_STAND_STATE_STAND);
+            target->SetStandState(UNIT_STAND_STATE_STAND);
             target->HandleEmoteCommand(EMOTE_STATE_NONE);
         }