Chance of infinite game-over softlock during Chaos Mode due to Party Randomization

[ShrineFox]

• This bug appeared after commit 1151643 which was meant to fix Issue Party reduced to Jeff only extremely often in Chaos Mode #16, so it's most likely related to that implementation
• EarthBound is known for this behavior when all members are removed from the party, even for a brief moment.
• I thought I had safeguards in place to prevent this from happening (i.e. adding the new party members before removing the others), but evidently they don't work correctly