Fix Meloetta-related bugs in mono-type challenges (#4460)

Remove Meloetta from the `TYPE_OVERRIDES` array so wrong-form
Meloetta can't be sent into battle.
This was missed when Meloetta was changed in a previous PR

Also disallow Meloetta from being added to the party in
starter select if it's in the wrong form
for the current mono-type challenge

src/data/challenge.ts

@@ -527,18 +527,19 @@ interface monotypeOverride {
  */
 export class SingleTypeChallenge extends Challenge {
   private static TYPE_OVERRIDES: monotypeOverride[] = [
-    {species: Species.MELOETTA, type: Type.PSYCHIC, fusion: true},
     {species: Species.CASTFORM, type: Type.NORMAL, fusion: false},
   ];
+  // TODO: Find a solution for all Pokemon with this ssui issue, including Basculin and Burmy
+  private static SPECIES_OVERRIDES: Species[] = [Species.MELOETTA];
 
   constructor() {
     super(Challenges.SINGLE_TYPE, 18);
   }
 
-  applyStarterChoice(pokemon: PokemonSpecies, valid: Utils.BooleanHolder, dexAttr: DexAttrProps, soft: boolean = false): boolean {
+  override applyStarterChoice(pokemon: PokemonSpecies, valid: Utils.BooleanHolder, dexAttr: DexAttrProps, soft: boolean = false): boolean {
     const speciesForm = getPokemonSpeciesForm(pokemon.speciesId, dexAttr.formIndex);
     const types = [speciesForm.type1, speciesForm.type2];
-    if (soft) {
+    if (soft && !SingleTypeChallenge.SPECIES_OVERRIDES.includes(pokemon.speciesId)) {
       const speciesToCheck = [pokemon.speciesId];
       while (speciesToCheck.length) {
         const checking = speciesToCheck.pop();