Adjusted file list banner background colour in dark mode

Signed-off-by: Daniel Bailey <daniel.bailey@grappleIT.co.uk>

src/main/res/values-night/colors.xml

@@ -34,6 +34,8 @@
     <color name="action_mode_status_bar_background">#ECECEC</color>
     <color name="selected_item_background">#757575</color>
 
+    <color name="filelist_icon_background">#222222</color>
+
     <color name="drawer_menu_icon">#ffffff</color>
     <color name="bg_fallback_highlight">#737373</color>
     <color name="switch_thumb_color_unchecked">#2a2a2a</color>