Increase notification icon brightness

Bug: 5526912
Change-Id: Ieca2160bc3ecfc11dc2196491a74956d7554eaa5

Author: Justin Ho

packages/SystemUI/res/values/dimens.xml

@@ -57,7 +57,7 @@
     <dimen name="status_bar_icon_drawing_size">18dip</dimen>
 
     <!-- opacity at which Notification icons will be drawn in the status bar -->
-    <item type="dimen" name="status_bar_icon_drawing_alpha">50%</item>
+    <item type="dimen" name="status_bar_icon_drawing_alpha">55%</item>
 
     <!-- gap on either side of status bar notification icons -->
     <dimen name="status_bar_icon_padding">0dp</dimen>