Fix: steal box not working properly

[Alessandro624]

Problem

When two or more bombs had the same timer value and exploded in the same turn, only the ones still present in self.bombs were considered for propagation. This happened because exploded bombs were already removed from self.bombs during self.tick_bombs().

As a result, in self.propagate_explosions(), the following loop:

for other_bomb in self.bombs:

would miss bombs that had already exploded in the same turn, even though they could still block the explosion chain. This led to explosions incorrectly continuing beyond those bombs, violating the intended behavior.

Test coverage

This fix addresses cases like the test_bomb_steals_box, where two bombs explode in the same turn, one triggering the other. Previously, one bomb could remain incorrectly in self.bombs, or explosions could pass through exploded bombs. After this fix, both bombs are properly removed and propagation behaves as expected.