* Applies #55457 (#56202)
A Pipeline that should've died when its last atmos component got deleted hasn't died, because of SSair.networks. Now they die. Its non-existence grants a lilliputian performance improvement to SSAIR_PIPENETS. airs[i] qdel is mostly about being thorough; every component has a gas mixture for each node all the time by default.
* Re-PR of #55457 ([Port] Atmos components now nullifies node properly)
Co-authored-by: Xenomedes <park246824@gmail.com>