Explosion: Recalculate light on destroyed blocks

this has been a bug for a long long time. I think the reason it was never addressed is because of the performance impact associated with it. However, that performance impact is now gone thanks to light update batching.

src/pocketmine/level/Explosion.php

@@ -230,6 +230,7 @@ class Explosion{
 
 				$t->close();
 			}
+			$this->level->updateAllLight($block);
 
 			$pos = new Vector3($block->x, $block->y, $block->z);