Update taskbar background color to match overview's dark mode

Note that taskbar is intentionally dark even when dark theme is off, whereas overview changes to light.

Test: visual with a few wallpapers
Bug: 191614244
Change-Id: I30f8c2f04047ea26fa726c9e470b87637a6c502e
diff --git a/quickstep/res/values/colors.xml b/quickstep/res/values/colors.xml
index 167c7c3..2f24441 100644
--- a/quickstep/res/values/colors.xml
+++ b/quickstep/res/values/colors.xml
@@ -26,6 +26,6 @@
     <color name="all_apps_prediction_row_separator_dark">#3cffffff</color>
 
     <!-- Taskbar -->
-    <color name="taskbar_background">#101010</color>
+    <color name="taskbar_background">@color/overview_scrim_dark</color>
     <color name="taskbar_icon_selection_ripple">#E0E0E0</color>
 </resources>
\ No newline at end of file