Refactor /obj/screen to /atom/movable/screen (#19852)

Part of backend stuff required for #19188. Should probably be test
merged.

---------

Co-authored-by: Cody Brittain <cbrittain10@live.com>

code/modules/client/client_procs.dm

@@ -898,10 +898,10 @@ var/list/localhost_addresses = list(
 /atom/proc/is_auto_clickable()
 	return TRUE
 
-/obj/screen/is_auto_clickable()
+/atom/movable/screen/is_auto_clickable()
 	return FALSE
 
-/obj/screen/click_catcher/is_auto_clickable()
+/atom/movable/screen/click_catcher/is_auto_clickable()
 	return TRUE
 
 /**

code/modules/client/preferences.dm

@@ -286,7 +286,7 @@ var/list/preferences_datums = list()
 	if(istype(NP) && istype(NP.late_choices_ui)) // update character icon in late-choices UI
 		NP.late_choices_ui.update_character_icon()
 
-	var/obj/screen/BG= LAZYACCESS(char_render_holders, "BG")
+	var/atom/movable/screen/BG= LAZYACCESS(char_render_holders, "BG")
 	if(!BG)
 		BG = new
 		BG.appearance_flags = TILE_BOUND|PIXEL_SCALE|NO_CLIENT_COLOR
@@ -299,7 +299,7 @@ var/list/preferences_datums = list()
 
 	var/index = 0
 	for(var/D in GLOB.cardinal)
-		var/obj/screen/O = LAZYACCESS(char_render_holders, "[D]")
+		var/atom/movable/screen/O = LAZYACCESS(char_render_holders, "[D]")
 		if(!O)
 			O = new
 			LAZYSET(char_render_holders, "[D]", O)
@@ -328,7 +328,7 @@ var/list/preferences_datums = list()
 
 /datum/preferences/proc/clear_character_previews()
 	for(var/index in char_render_holders)
-		var/obj/screen/S = char_render_holders[index]
+		var/atom/movable/screen/S = char_render_holders[index]
 		client?.screen -= S
 		qdel(S)
 	QDEL_LIST_ASSOC_VAL(char_render_holders)

code/modules/client/ui_style.dm

@@ -48,7 +48,7 @@ var/all_tooltip_styles = list(
 
 	var/icon/ic = all_ui_styles[UI_style_new]
 
-	for(var/obj/screen/I in icons)
+	for(var/atom/movable/screen/I in icons)
 		if(I.name in list(I_HELP, I_HURT, I_DISARM, I_GRAB)) continue
 		I.icon = ic
 		I.color = UI_style_color_new