TGUI list conversions + bug fixes (#63354)

About The Pull Request

    Converts more inputs to TGUI. Possibly all user-facing input lists in the game.
    Did any surrounding text/number inputs as well
    Added null choice support so users can press cancel.
    Added some misc TGUI input fixes
    Fixed custom vendors while I was there

I refactored a lot of code while just poking around.
Primarily, usage of .len in files where I was already working on lists.
Some code was just awful - look at guardian.dm and its non use of early returns
If there are any disputes, I can revert it just fine, those changes are not integral to the PR.
Why It's Good For The Game

Fixes #63629
Fixes #63307
Fixes custom vendors /again/
Text input is more performant.
Part of a long series of TGUI conversion to make the game more visually appealing
Changelog

cl
refactor: The majority of user facing input lists have been converted to TGUI.
refactor: Tgui text inputs now scale with entered input.
fix: Many inputs now properly accept cancelling out of the menu.
fix: Fixes an edge case where users could not press enter on number inputs.
fix: Custom vendor bluescreen.
fix: You can now press ENTER on text inputs without an entry to cancel.
/cl

code/modules/mining/fulton.dm

@@ -19,23 +19,17 @@ GLOBAL_LIST_EMPTY(total_extraction_beacons)
 
 /obj/item/extraction_pack/attack_self(mob/user)
 	var/list/possible_beacons = list()
-	for(var/B in GLOB.total_extraction_beacons)
-		var/obj/structure/extraction_point/EP = B
-		if(EP.beacon_network in beacon_networks)
-			possible_beacons += EP
-
-	if(!possible_beacons.len)
+	for(var/obj/structure/extraction_point/extraction_point as anything in GLOB.total_extraction_beacons)
+		if(extraction_point.beacon_network in beacon_networks)
+			possible_beacons += extraction_point
+	if(!length(possible_beacons))
 		to_chat(user, span_warning("There are no extraction beacons in existence!"))
 		return
-
 	else
-		var/A
-
-		A = input("Select a beacon to connect to", "Balloon Extraction Pack", A) as null|anything in sort_names(possible_beacons)
-
-		if(!A)
+		var/chosen_beacon = tgui_input_list(user, "Beacon to connect to", "Balloon Extraction Pack", sort_names(possible_beacons))
+		if(isnull(chosen_beacon))
 			return
-		beacon = A
+		beacon = chosen_beacon
 		to_chat(user, span_notice("You link the extraction pack to the beacon system."))
 
 /obj/item/extraction_pack/afterattack(atom/movable/A, mob/living/carbon/human/user, flag, params)