Fix corner-case runtimes for removed jobs, other minor fixes (#94822)

* Fix runtimes in `/datum/id_trim` and when equipping corpses if a map's
.json file fully removes a job
* Remove unused `/datum/powernet/var/number`
* Fix ctrl+clicking a telescreen to mute it also activating it normally
* Unmark `_liver.dm` as executable

code/datums/id_trim/jobs.dm

@@ -25,6 +25,9 @@
 /datum/id_trim/job/New()
 	if(ispath(job))
 		job = SSjob.get_job_type(job)
+		if (isnull(job))
+			// Not a valid job. Maybe removed by the map.
+			return
 
 	if(isnull(job_changes))
 		job_changes = SSmapping.current_map.job_changes