Use dynamic variable and condense menu-label syntax

The label is jumped to and not called, but the variable will still clean itself up eventually

(cherry picked from commit 4c52d1638f)

game/scripts/rooms/main_room/objects/jerk_off.rpy

@@ -1,6 +1,3 @@
-
-default jerk_off_choice = None # Last jerk-off fantasy
-
 label jerk_off:
     call gen_chibi("jerk_off_behind_desk")
     with d3
@@ -8,8 +5,9 @@ label jerk_off:
 
     gen "(How should I finish this thing?)" ("base", xpos="far_left", ypos="head")
 
-    label .choice:
-    menu:
+    $ renpy.dynamic(jerk_off_choice=None)
+
+    menu .choice:
         "-Hermione's panties!-" if states.her.ev.panty_thief.acquired:
             $ jerk_off_choice = "hermione"
             $ states.her.ev.panty_thief.soaked = True