Fix pokewalker pid check for female-only

pidGender check failed as 0xFE (female only) returned male if pid ended
in 0xFE or 0xFF
jump out early if the pkm is fixed gender rather than genderless only

https://projectpokemon.org/home/forums/topic/48956-pokewalker-happiny-pid-mismatch/
Thanks Taargüs Taargüs!

PKHeX.Core/Legality/RNG/PIDGenerator.cs

@@ -230,18 +230,18 @@ public static uint GetPokeWalkerPID(int TID, int SID, uint nature, int gender, i
             // Ensure nature is set to required nature without affecting shininess
             pid += nature - (pid % 25);
 
+            if (gr >= 0xFE || gr == 0) // non-dual gender
+                return pid;
+
             // Ensure Gender is set to required gender without affecting other properties
             // If Gender is modified, modify the ability if appropriate
-            int currentGender = gender;
-            if (currentGender == 2)
-                return pid;
 
             // either m/f
             var pidGender = (pid & 0xFF) < gr ? 1 : 0;
-            if (currentGender == pidGender)
+            if (gender == pidGender)
                 return pid;
 
-            if (currentGender == 0) // Male
+            if (gender == 0) // Male
             {
                 pid += (uint)((((gr - (pid & 0xFF)) / 25) + 1) * 25);
                 if ((nature & 1) != (pid & 1))