Canreach refactor (#93165)

## About The Pull Request
ports https://github.com/DaedalusDock/daedalusdock/pull/1144
ports https://github.com/DaedalusDock/daedalusdock/pull/1147

full credit to @Kapu1178 for the juice

instead of `reacher.CanReach(target)` we now do
`target.CanBeReachedBy(reacher)`, this allows us to give special
behavior to atoms which we want to reach, which is exactly what I need
for a feature I'm working on.
## Why It's Good For The Game
allows us to be more flexible with reachability
## Changelog
🆑
refactor: refactored how reaching items works, report any oddities with
being unable to reach something you should be able to!
/🆑

code/modules/mob/living/basic/bots/dedbot.dm

@@ -109,7 +109,7 @@
 
 /datum/action/cooldown/mob_cooldown/exenterate/proc/slash_em(atom/caster)
 	for(var/mob/living/victim in range(ability_range, caster))
-		if(faction_check(victim.faction, immune_factions) && owner.CanReach(victim))
+		if(faction_check(victim.faction, immune_factions) && victim.IsReachableBy(owner))
 			continue
 		to_chat(caster, span_warning("You slice [victim]!"))
 		to_chat(victim, span_warning("You are cut by [caster]'s blades!"))

code/modules/mob/living/basic/bots/medbot/medbot.dm

@@ -366,7 +366,7 @@
 		update_bot_mode(new_mode = BOT_IDLE)
 		return
 
-	if(CanReach(patient))
+	if(patient.IsReachableBy(src))
 		melee_attack(patient)
 
 /datum/id_trim/medibot