SoF:09: Update final fade out effect to use screen_fade

* Changed FADE_TO_BLACK to SCREEN_FADE_OUT
* Updated the red [color_adjust] to [screen_fade]. Also tweaked the
  timing to make it flow smoothly.
* Removed the now-unnecessary kill tag used to hide units before
  the fade.

data/campaigns/Sceptre_of_Fire/scenarios/9_Caverns_of_Flame.cfg

@@ -936,20 +936,13 @@
             [redraw]
                 side=1
             [/redraw]
-            [delay]
-                time=300
-            [/delay]
-            [color_adjust]
-                red=255
-                green=-100
-                blue=-180
-            [/color_adjust]
-            [kill]
-                x=1-44
-                animate=no
-                fire_event=no
-            [/kill]
-            {FADE_TO_BLACK}
+            # fade to red then fade out
+            [screen_fade]
+                red,green,blue=255,0,0
+                alpha=200
+                duration=600
+            [/screen_fade]
+            {SCREEN_FADE_OUT}
             # Check if the player had a Gryphon Rider or Gryphon Master before all units were killed.
             [if]
                 [variable]