Remove species form encounter code for Scatterbug line and Calyrex

The Vivillon forms can all be encountered properly now, and Calyrex's forms have since been removed from the wild encounter pool, requiring a form change item to obtain.

src/battle-scene.ts

@@ -987,6 +987,8 @@ export default class BattleScene extends SceneBase {
 			case Species.SAWSBUCK:
 			case Species.FROAKIE:
 			case Species.FROGADIER:
+			case Species.SCATTERBUG:
+			case Species.SPEWPA:
 			case Species.VIVILLON:
 			case Species.FLABEBE:
 			case Species.FLOETTE:

src/field/arena.ts

@@ -179,10 +179,6 @@ export class Arena {
             return 5;
         }
         break;
-      case Species.SCATTERBUG:
-      case Species.SPEWPA:
-      case Species.VIVILLON:
-        return 0;
       case Species.LYCANROC:
         const timeOfDay = this.getTimeOfDay();
         switch (timeOfDay) {
@@ -194,13 +190,6 @@ export class Arena {
           case TimeOfDay.NIGHT:
             return 1;
         }
-      case Species.CALYREX:
-        switch (this.biomeType) {
-          case Biome.SNOWY_FOREST:
-            return 1;
-          case Biome.GRAVEYARD:
-            return 2;
-        }
         break;
     }