Crash when breaking random item box with no sidekick or stocks in Encore Mode

[MegAmi24]

Steps to reproduce:

1. Boot up game, start a new game in Encore Mode
2. When you get to GHZ, die as one of the characters, don't get any new stocks before or afterwards
3. Break a random item box

randomcrash.mp4

[MegAmi24]

Looked in VS Debugger, there are two things causing this:

1. The game is supposed to play the swap fail sfx when there is no P2, but for some reason the check for it always returns false. My guess is there's an error in HUD_CharacterIndexFromID.

   Sonic-Mania-Decompilation/SonicMania/Objects/Global/ItemBox.c

   Lines 591 to 596 in 75b3784

   	playerIDs[0] = HUD_CharacterIndexFromID(player1->characterID);
   	playerIDs[1] = HUD_CharacterIndexFromID(player2->characterID);
   	if (playerIDs[1] == 0xFF) {
   	RSDK.PlaySfx(Player->sfxSwapFail, false, 255);
   	}

2. There's an infinite loop in the randomizing code, with the if ((1 << newPlayerIDs[p]) & globals->characterFlags) check always returning false and p never incrementing. This was also reported in Game freezes when collecting question mark powerup in SPZ Encore Mode #264.

   Sonic-Mania-Decompilation/SonicMania/Objects/Global/ItemBox.c

   Lines 607 to 614 in 75b3784

   	int32 p = 0;
   	for (; p < 5;) {
   	bool32 inc = true;
   	if (playerIDs[p] == 0xFF)
   	break;
   	newPlayerIDs[p] = RSDK.Rand(0, 5);
   	if ((1 << newPlayerIDs[p]) & globals->characterFlags) {