Fix explosion layer mask

Author: adamgraham

Assets/Scenes/Bomberman.unity

@@ -1464,7 +1464,7 @@ MonoBehaviour:
   explosionPrefab: {fileID: 805732483383335703, guid: 7d7e9c7ce1308484e863a8b4489e090f, type: 3}
   explosionLayerMask:
     serializedVersion: 2
-    m_Bits: 192
+    m_Bits: 64
   explosionDuration: 1
   explosionRadius: 1
   destructibleTiles: {fileID: 1169247074}