Update Avalanche to be Single Target (#4581)

Avalanche is a single target move in doubles.
Currently it is bugged to be a spread move this change corrects that.

Source:
https://bulbapedia.bulbagarden.net/wiki/Avalanche_(move)

src/data/moves_info.h

@@ -10084,7 +10084,7 @@ const struct MoveInfo gMovesInfo[MOVES_COUNT_DYNAMAX] =
         .type = TYPE_ICE,
         .accuracy = 100,
         .pp = 10,
-        .target = MOVE_TARGET_BOTH,
+        .target = MOVE_TARGET_SELECTED,
         .priority = -4,
         .category = DAMAGE_CATEGORY_PHYSICAL,
         .makesContact = TRUE,