Fixes revelation program (#73463)

## About The Pull Request

#70678 removed hard drives from the game, and made the files be stored
directly on the computer. However, revelation has not been updated in
this regard. This PR once again makes it delete all files.

In addition, revelation also had a big red button yelling "activate"
that did nothing, and an option in ui_act that said "PRG_activate", that
wasn't used by anything, so I have linked up the two, allowing you to
revelate immediately. This does not feel like a real change, since you
could do this by arming, closing, and then reopening the program.

## Why It's Good For The Game

Fixes #72682

## Changelog

🆑
fix: Revelation once again wipes the stored files on the computer
/🆑

code/modules/modular_computers/file_system/programs/antagonist/revelation.dm

@@ -28,14 +28,17 @@
 		computer.visible_message(span_notice("\The [computer]'s screen brightly flashes and loud electrical buzzing is heard."))
 		computer.enabled = FALSE
 		computer.update_appearance()
+
+		QDEL_LIST(computer.stored_files)
+
 		computer.take_damage(25, BRUTE, 0, 0)
+
 		if(computer.internal_cell && prob(25))
 			QDEL_NULL(computer.internal_cell)
 			computer.visible_message(span_notice("\The [computer]'s battery explodes in rain of sparks."))
 			var/datum/effect_system/spark_spread/spark_system = new /datum/effect_system/spark_spread
 			spark_system.start()
 
-
 /datum/computer_file/program/revelation/ui_act(action, params)
 	. = ..()
 	if(.)