Adds some throwing datum nullchecks (#91720)

## About The Pull Request

A few places seem to call `hitby` or `throw_impact` without a throwing
datum to mimic the effect of colliding with something, which is cringe,
but I guess we should support it.

So we need to nullcheck for `get_thrower`, else it runtimes and cancels
the whole proc.

## Changelog

🆑 Melbert
fix: Glass shards from colliding with vendors or glass table hurt you
again.
/🆑

code/modules/projectiles/guns/ballistic/pistol.dm

@@ -102,7 +102,7 @@
 	if(.)
 		return
 	var/obj/projectile/energy/fisher/melee/simulated_hit = new
-	simulated_hit.firer = throwingdatum.get_thrower()
+	simulated_hit.firer = throwingdatum?.get_thrower()
 	simulated_hit.on_hit(hit_atom)
 
 /obj/item/gun/ballistic/automatic/pistol/m1911

code/modules/projectiles/guns/energy/recharge.dm

@@ -168,5 +168,5 @@
 	// ...you reeeeeally just shoot them, but in case you can't/won't
 	. = ..()
 	var/obj/projectile/energy/fisher/melee/simulated_hit = new
-	simulated_hit.firer = throwingdatum.get_thrower()
+	simulated_hit.firer = throwingdatum?.get_thrower()
 	simulated_hit.on_hit(hit_atom)