Tram mob throwing adjustments (#81617)

## About The Pull Request

- Corrects grille breaking related to PR
https://github.com/tgstation/tgstation/pull/81594
- Throw chance moved to a var on the controller instead of hardcoded
- Corrects a bit of documentation on tram controller landmarks
- Fixes the collision multiplier being set to a static value during
malfunction instead of the intended multiplier
- Includes throw chance in tram malfunction
- Cursed mobs now guaranteed to be thrown

## Changelog

🆑 LT3
code: Tram throwing now breaks grilles consistently
code: Tram malfunction lethality/throw chance are now a multiplier
instead of flat value
code: Tram throw chance can be adjusted
code: Unlucky trait is now used in tram throw calculation 
/🆑

---------

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/modules/transport/linear_controller.dm

@@ -35,6 +35,9 @@
 	///if true, the platform cannot be manually moved.
 	var/controls_locked = FALSE
 
+	/// probability of being thrown hard during an emergency stop
+	var/throw_chance = 17.5
+
 /datum/transport_controller/linear/New(obj/structure/transport/linear/transport_module)
 	transport_id = transport_module.transport_id
 	create_modular_set = transport_module.create_modular_set