Prevent end_round duplication and ensure life loss when entire deck is discarded prior to playing any hands

[acbeard]

This PR addresses an issue where returning no value during the end_round call caused the function to be called again, resulting in infinite double-end prevention.

Enhanced the value being used to detect "stop ends" into being an MP.GAME var for "round_ended".

[acbeard]

This still does not address the issue where if the deck is fully discarded during a blind, the number of lives will not decrement. Based on where the fail_round call currently exists, I think round failure may need to be reworked slightly, or for a check of this particular case to exist on end_round and decrement the life total.

[acbeard]

Add life loss calculation for the edge case where a player plays no hands and discards their entire deck.

Added handling during end_round that advances any pvp rounds where this occurs.

Tested from both sides during a pvp blind, and validated life loss behavior only occurs during the desired condition.

[acbeard]

This behavior update still does not correct the situation for the Survival game mode, open to any ideas for how that can be approached!

That said, I think this is worth incorporation to correct other game modes even if a survival solution is not found. Prevented fail_round call during survival so life loss gold will not be awarded incorrectly.