Fix DocumentsUI did not meet Google Accessibility Rating (GAR) criteria

To meet GAR criteria contrast ratio should at least 4.5:1
1.Fine tune ToolBar Icon and Text Color to full 100% white #FFFFFFFF
2.Modify ToolBar, Drawer header background and CheckBox color to #FF1A73E8
3.Enlarge TextSize of Dropdown sort component from 14sp(56px) to 18sp(72px)
4.Enlarge arrow icon from 36dp to 48dp

Bug: 79710817
Test: atest DocumentsUITests
Change-Id: I60ec0888fb793142f0974647c5e43b0a07bf6080
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 7eadccc..b720c33 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -52,7 +52,8 @@
     <dimen name="doc_header_height">60dp</dimen>
 
     <dimen name="dropdown_sort_widget_margin">12dp</dimen>
-    <dimen name="dropdown_sort_widget_size">36dp</dimen>
+    <dimen name="dropdown_sort_widget_size">48dp</dimen>
+    <dimen name="dropdown_sort_text_size">18sp</dimen>
 
     <dimen name="drop_icon_height">14dp</dimen>
     <dimen name="drop_icon_width">14dp</dimen>