Soul Sand / Magma underwater effects should pass through iron bars!

Here's a simple QoL feature! We always get our feet burnt when using downwards water elevators with magma at the bottom. To mitigate that, waterlogged iron bars (and maybe other blocks that would make sense, like glass panes, iron trapdoors or leaves) should let the up-lifting effect of soul sand and the sinking pull of magma pass through it! In other words, the game should treat the waterlogged bars as an "empty" water source block whilst letting the iron bars act as a physical separator between the magma / soul sand and the bubble column itself.