Fix GS Ball unlock functionality

It was reported by /u/ImranFZakhaev on reddit that receiving the GS Ball
doesn't actually unlock the event. So I implemented it in a different
way.

By writing 0xB to 0x3E3C, we can start the GS Ball event semi-legit.
After triggering the GS Ball event from PokeMe64, you need to go to and
leave the Golden Rod Pokemon Center and an attendant will appear to hand
you the GS Ball.

src/menu/MenuEntries.cpp

@@ -43,7 +43,7 @@ MenuItemData gen2CrystalMenuEntries[] = {
         .onConfirmAction = goToGen2PCNYDistributionPokemonMenu,
     },
     {
-        .title = "Receive GS Ball",
+        .title = "Unlock GS Ball",
         .onConfirmAction = gen2ReceiveGSBall
     }
 };