Stops unessassary reactions from occurring in plumbing machines (#95125)

## About The Pull Request
This PR stops reactions from occurring in plumbing machines except for 2
- Reaction chamber
- Acclimator

This means you can now have a tank containing welding fuel, carbon &
hydrogen and not worry about them reacting to create oil

## Why its good for the game
- Makes the game run faster. Calling `handle_reactions()` is an
expensive operation and should not be done needlessly
- Makes life for players easier. We don't want chemicals reacting before
they reach the reaction chamber & acclimator and making them obsolete.
It now allows them to do their job properly

**Dependencies**
- #95077
- #95084

After they are merged. Part of their code needs to be rewritten here.

This also deletes the redundant splitter sprite

## Changelog
🆑
qol: except for plumbing reaction chamber & acclimator, no reactions
will occur inside plumbing machines
/🆑

code/modules/asset_cache/assets/plumbing.dm

@@ -24,7 +24,7 @@
 			"manifold",
 			"pipe_input",
 			"filter",
-			"splitter_tri",
+			"splitter",
 			"beacon",
 			"pipe_output",
 			"tank",