Better item selected background color in dark mode

Signed-off-by: Joris Bodin <joris.bodin@infomaniak.com>

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

@@ -32,7 +32,7 @@
 
     <!-- Multiselect backgrounds -->
     <color name="action_mode_background">@color/appbar</color>
-    <color name="selected_item_background">#757575</color>
+    <color name="selected_item_background">#373535</color>
 
     <color name="filelist_icon_background">#222222</color>